The bug
Evoker spawn eggs disappear when upgrading from 1.12.2 to 1.13-pre5. Probably related to the ID changes. Other spawn eggs are not affected however.
Warning from log:
[0630/211109:INFO:GameCallbacks.cpp(188)] game/alh (WorldGen-Scheduler-1) warn Unable to load item from: {Count:1b,id:"minecraft:evocation_illager_spawn_egg",tag:{EntityTag:{id:"minecraft:evocation_illager"}}}
Are you sure vindicator spawn eggs weren’t affected?