Posting this here as not sure if this is a Sponge issue or Better Advancment issue

I am currently running

SpongeForge version: spongeforge-1.12.2-2611-8.0.0-BETA-2993.jar

Forge version: forge-1.12.2-14.23.2.2635-universal.jar

Java version: Java openjdk version "1.8.0_151"
OpenJDK Runtime Environment (build 1.8.0_151-b12)
OpenJDK 64-Bit Server VM (build 25.151-b12, mixed mode)

Operating System: CentOS release 6.8 (Final)

Plugins/Mods:
Sevtech Modpack 3.0.4

Issue Description
So the issue is to do with Better Advancments for the progression of the modpack, a player will be able to complete quests but the items which or forbidden origionally will still stay forbidden, so for instance if slot 8 in my inventory is highlighted i will be able to puck up the item but as soon as i move over to slot 1 it will drop out the item and say I am not able to use this item yet.

I have tested with out sponge and do not have this problem but when sponge is installed this will occur

One Error i did see on joining: https://pastebin.com/kdtm39Fq

Not a better advancements issue.

Error seems to be related to me.lucko.luckperms.sponge.service.proxy.api7.PermissionServiceProxy cannot be cast to org.spongepowered.common.interfaces.IMixinCommandSender

It seems like you changed quite some things to the pack, both LuckPerms and Sponge are not in the pack by default. When adding/changing mods in a pack you should always check whether it are those mods first.