MC 1.20.1, Forge 47.3.5, only latest (1.0.2) version of the Spawn mod installed in server (tested without any additional mods).

[Worker-Main-3/ERROR] [minecraft/TagLoader]: Couldn't load tag spawn:small_anthill_generates as it is missing following references: #c:savanna (from Spawn (1.0.2).jar),
#c:plains (from Spawn (1.0.2).jar)

[main/ERROR] [minecraft/ServerAdvancementManager]: Parsing error loading custom advancement spawn:husbandry/hatch_ant: Invalid criterion trigger: spawn:hatch_ant

Full log – latest (8).log