When loading a chunk, sometimes all tiles in a chunk will be invisible until updated by a block update.

https://imgur.com/a/sjyG1on

http://prntscr.com/qs13rf Latest version installed.
Optifine is not installed.

I have uploaded a pre-release in the discord server. It fixes the issue, but it's quite unstable.

Requires newest version of CreativeCore
LittleTiles https://cdn.discordapp.com/attachments/326729168266199040/670575574879567892/LittleTiles_v1.5.0-pre199_mc1.12.2.jar
OnlinePictureFrame https://cdn.discordapp.com/attachments/326729168266199040/670229596406415370/OnlinePicFrame_v1.4.34_mc1.12.2.jar

I will upload it to curseforge once it's stable.

With pre199 or using pre198?

CreativeCore 1.9.90
LittleTiles pre198

Sorry, I was a bit unclear

Just download the version from above and the issue should be fixed. I will upload it to curseforge soon.

Ok nice, thanks. What did you mean about it being unstable though?

It was quite unstable, but a few people have tested it already. I have fixed those issue, so it should be stable now.

That's great to hear, thank you for your diligence!

Yep, same issue:

This Problem still reappear in LT-pre199 on server.

@HeidFanatic do you have vanillafix installed?

I do @CreativeMD

@Tschipp Can you remove it and see if it still happens?

@CreativeMD no vanillafix, no any other optmization mod.

@HeidFanatic can you send me your mod list?

@CreativeMD
Here is modlist of server, which doesn't indclude LT, CreativeCore, OPF due to the invisibility bug.
[14:46:20] [main/DEBUG] [FML]: Examining file: animania-1.12.2-1.7.3.jar
[14:46:20] [main/DEBUG] [FML]: Examining file: armoryexpansion-1.4.1.jar
[14:46:20] [main/DEBUG] [FML]: Examining file: Baubles-1.12-1.5.2.jar
[14:46:20] [main/DEBUG] [FML]: Examining file: bettercaves-1.12.2-1.6.0.jar
[14:46:20] [main/DEBUG] [FML]: Examining file: BiomesOPlenty-1.12.2-7.0.1.2441-universal.jar
[14:46:20] [main/DEBUG] [FML]: Examining file: BiomesYouGo1.7.1.jar
[14:46:20] [main/DEBUG] [FML]: Examining file: bonsaitrees-1.1.4-b170.jar
[14:46:20] [main/DEBUG] [FML]: Examining file: BuildingGadgets-2.7.4.jar
[14:46:20] [main/DEBUG] [FML]: Examining file: CarryOn+MC1.12.2+v1.12.3.jar
[14:46:20] [main/DEBUG] [FML]: Examining file: Chameleon-1.12-4.1.3.jar
[14:46:20] [main/DEBUG] [FML]: Examining file: Chisel-MC1.12.2-1.0.1.44.jar
[14:46:20] [main/DEBUG] [FML]: Examining file: conarm-1.12.2-1.2.5.3.jar
[14:46:20] [main/DEBUG] [FML]: Examining file: CraftStudioAPI-universal-1.0.1.95-mc1.12-alpha.jar
[14:46:20] [main/DEBUG] [FML]: Examining file: creeperconfetti-1.4.2.jar
[14:46:20] [main/DEBUG] [FML]: Examining file: CustomNPCs_1.12.2-(01Oct19).jar
[14:46:20] [main/DEBUG] [FML]: Examining file: ElectroblobsWizardry-4.2.7-MC1.12.2.jar
[14:46:20] [main/DEBUG] [FML]: Examining file: Farseek-1.12-2.4.jar
[14:46:20] [main/DEBUG] [FML]: Examining file: furniture-6.3.1-1.12.2.jar
[14:46:20] [main/DEBUG] [FML]: Examining file: future-mc-0.1.13.jar
[14:46:20] [main/DEBUG] [FML]: Examining file: Hwyla-1.8.26-B41_1.12.2.jar
[14:46:20] [main/DEBUG] [FML]: Examining file: ido-1.12.2-1.1.0.jar
[14:46:20] [main/DEBUG] [FML]: Examining file: InventoryTweaks-1.63.jar
[14:46:20] [main/DEBUG] [FML]: Examining file: IvToolkit-1.3.3-1.12.jar
[14:46:20] [main/DEBUG] [FML]: Examining file: jei_1.12.2-4.15.0.291.jar
[14:46:20] [main/DEBUG] [FML]: Examining file: journeymap-1.12.2-5.5.6.jar
[14:46:20] [main/DEBUG] [FML]: Examining file: Mantle-1.12-1.3.3.55.jar
[14:46:20] [main/DEBUG] [FML]: Examining file: Mekanism-1.12.2-9.8.3.390.jar
[14:46:20] [main/DEBUG] [FML]: Examining file: MekanismGenerators-1.12.2-9.8.3.390.jar
[14:46:20] [main/DEBUG] [FML]: Examining file: NaturesCompass-1.12.2-1.8.3.jar
[14:46:20] [main/DEBUG] [FML]: Examining file: plustic-7.1.6.1.jar
[14:46:20] [main/DEBUG] [FML]: Examining file: RecurrentComplex-1.4.8.2.jar
[14:46:20] [main/DEBUG] [FML]: Examining file: SereneSeasons-1.12.2-1.2.18-universal.jar
[14:46:20] [main/DEBUG] [FML]: Examining file: StorageDrawers-1.12.2-5.4.0.jar
[14:46:20] [main/DEBUG] [FML]: Examining file: Streams-1.12-0.4.7.jar
[14:46:20] [main/DEBUG] [FML]: Examining file: taiga-1.12.2-1.3.4.jar
[14:46:20] [main/DEBUG] [FML]: Examining file: TConstruct-1.12.2-2.13.0.171.jar
[14:46:20] [main/DEBUG] [FML]: Examining file: UndergroundBiomesConstructs-1.12-1.3.7.jar
[14:46:20] [main/DEBUG] [FML]: Examining file: Waystones_1.12.2-4.1.0.jar
[14:46:20] [main/DEBUG] [FML]: Examining file: worldedit-forge-mc1.12.2-6.1.10-SNAPSHOT-dist.jar
[14:46:20] [main/DEBUG] [FML]: Examining file: [Client-side]Blur-1.0.4-14.jar
[14:46:20] [main/DEBUG] [FML]: Examining file: [Client-side]ClockHUD-1.12-1.4.0.jar
[14:46:20] [main/DEBUG] [FML]: Examining file: [Client-side]CTM-MC1.12.2-1.0.1.30.jar
[14:46:20] [main/DEBUG] [FML]: Examining file: [Client-side]CustomSkinLoader_Forge-14.9.jar
[14:46:20] [main/DEBUG] [FML]: Examining file: [Client-side]i18nupdatemod-1.12.2-1.0.8.jar
[14:46:20] [main/DEBUG] [FML]: Examining file: [Client-side]JustEnoughCharacters-1.12.0-3.4.5.jar
[14:46:20] [main/DEBUG] [FML]: Examining file: [Client-side]mod_autofish_forge-1.12-1.7.jar
[14:46:20] [main/DEBUG] [FML]: Examining file: [Client-side]OptiFine_1.12.2_HD_U_F5.jar
[14:46:20] [main/DEBUG] [FML]: Examining file: [Client-side]SmoothFont-mc1.12.2-2.1.1.jar

In case it helps, I've noticed that LT objects not being visible is a per-chunk effect. A block update anywhere in that chunk will cause them all to re-appear. Until then, only their collision boxes are visible when you approach. My tests were on a server. Anyone logging in (I used LT in the spawn building) seems to not be able to see some LT objects in their vicinity prior to a chunk-localized block update. Whether something is visible or not is definitely chunk-defined. In the attached image, of two bed frames made from an Advanced Recipe in creative (so the whole thing breaks as one) half of one is visible in one chunk, while the other half in another chunk is not. Opening a door in that other chunk makes the whole frame visible.

The second image is after the door was opened. Note that, along with the other half of the bed frame, the planters on either side of the door also appeared after the door in that chunk was opened.

Version 1.5.0_pre198 was used in these tests along with CreativeCore 1.9.90 on a server running ATM3-Remix (with those two mods added in).

EDIT:
For my spawn building, I tried putting a piston in each chunk down at bedrock, all tied to a redstone clock. However, this didn't have the effect I wanted of resetting the LT invisibility every time it fired. Instead, I dug a chamber just below the floor and did the same, this time tying them all to a single pressure plate at the spawn location. Now whenever anyone logs in for the first time or uses /spawn, they reset the blocks' visibility by landing on the pressure plate and triggering the pistons in each chunk once.

But a fix would be better. ;)

@Nonsanity yeah, that's the exact same issue. You have to download pre199 in order to fix it, but keep in mind this version might have some other bugs (that's why it's not released yet).

@Tschipp if you remove VanillaFix everything should work just fine.

@HeidFanatic Can you remove all mods except of CreativeCore and LittleTiles. Would be interesting to know if the issue still occurs.

I’m afraid I’ll have to wait for the next release to update my server. I’m already asking each of the players to modify the pack through the Twitch launcher (JUST because I love LittleTiles), I can’t really ask or expect them to do it completely manually. If that changes, I’ll update my results—along with any new issues that the pre199 version introduces.

@Nonsanity I'm waiting for Dynamic Surroundings to release the update as well (because pre199 is incompatible with it).

This version should fix it entirely:
https://cdn.discordapp.com/attachments/326729168266199040/676148113328570398/LittleTiles_v1.5.0-pre199_8_mc1.12.2.jar

The version has been released officially.