Testing in Singleplayer, using the following vanilla command:
/give @s minecraft:bat_spawn_egg{EntityTag:{id:"minecraft:experience_orb",Count:65538,Value:32767s,CustomName:''}} 1
You will get a bat egg which should spawn an XP orb giving thousands of levels.
In Fabric, WITHOUT Clumps: It works, the orb starts multiplying and spamming XP levels onto the player.
In Fabric, INCLUDING Clumps: The spawned XP orb from the egg gives no XP.

For comparison, the summon command:
/summon experience_orb ~ ~ ~7 {Count:65538,Value:32767s,CustomName:''}
...works both with or without Clumps.

Inspecting the egg-spawned XP orb from Clumps using /data get I noticed Count is intact, but Value is destroyed and set to zero.

Versions:

• Minecraft 1.20 (no, not 1.20.1)
• Fabric 0.14.21
• Clumps 11.0.0.1

Should be working now, let me know if you run into any other issues