Modpack version
0.5.2 (I'm not using the release because it crashed my game whenever I entered my world)

Describe the bug
Whenever experience orbs are spawned, and with no exception, they disappear instantly making it impossible to pick up.
I tested this on multiple cases:

• Ender dragon
• Regular mob
• Grindstone
• Furnace

All of them had the same results, the experience orbs disappeared. This is very annoying as I'm trying to do some enchanting and currently my only way of getting experience is by using /xp and assuming the experience amount I was supposed to get.

Logs
Probably not needed, but here it is anyway.
latest.log

Just went in a brand new creative world to try this, same thing happens.

Can you delete the Clumps mod and see if it still happens?

You are using an ancient version of Java 8. I highly recommend that you update.

This message should not be appearing on your log: [main/WARN]: LEGACY JDK DETECTED, SECURED JAR HANDLING DISABLED

Download here: https://adoptopenjdk.net/?variant=openjdk8&jvmVariant=hotspot (OpenJDK 8, Hotspot 292)

Can't reproduce this in creative or survival either.

Could you please provide your latest.log? :)

Not the issue and just downloading it will not make minecraft use it. The message is just fine and appears when you use the java version that ships with the game.

Since this happens in a creative world for him we would just need someone to confirm this?

You are using an ancient version of Java 8. I highly recommend that you update.

This message should not be appearing on your log: [main/WARN]: LEGACY JDK DETECTED, SECURED JAR HANDLING DISABLED

Download here: https://adoptopenjdk.net/?variant=openjdk8&jvmVariant=hotspot (OpenJDK 8, Hotspot 292)

I could've sworn I updated, I'll try updating again.

I could've sworn I updated, I'll try updating again.

As Darkere said this probably isn't the issue, my bad. Also even if you update you will have to configure the launcher to use that so idk do it if you want

I know, but either way it's better to have the latest version.

Since this happens in a creative world for him we would just need someone to confirm this?

I'm not being able to reproduce the issue in creative or survival.

I could've sworn I updated, I'll try updating again.

As Darkere said this probably isn't the issue, my bad. Also even if you update you will have to configure the launcher to use that so idk do it if you want

Yep updating java changed nothing.

The log was already provided in the original post. I can provide my current log if needed.

Oh derp, my bad.

[12:37:52] [Server thread/INFO]: Enable clustering of items with a radius of 4 blocks.
[12:37:52] [Server thread/INFO]: Enable clustering of Experience Orbs with a radius of 4 blocks.
[12:37:52] [Server thread/ERROR]: Clumps groups XP orbs together into a new single entity, which will conflict with the XP Orb feature of this mod. Don't use both optimizations together!

Found this in the log. Seems there's an extra mod in your instance :)
This one specifically: https://www.curseforge.com/minecraft/mc-mods/get-it-together-drops

Ah thanks, forgot I had that installed.

[12:37:52] [Server thread/INFO]: Enable clustering of items with a radius of 4 blocks.
[12:37:52] [Server thread/INFO]: Enable clustering of Experience Orbs with a radius of 4 blocks.
[12:37:52] [Server thread/ERROR]: Clumps groups XP orbs together into a new single entity, which will conflict with the XP Orb feature of this mod. Don't use both optimizations together!

Found this in the log. Seems there's an extra mod in your instance :)
This one specifically: https://www.curseforge.com/minecraft/mc-mods/get-it-together-drops

O.o I have these two both, for some reason it still didn't happen to me, the error isn't in my logs either.
Maybe this is some configuration file shenanigans, I don't even remember editing mine.