Modpack version
0.4.10

Describe the bug
To get the 'explorer' title from https://www.curseforge.com/minecraft/mc-mods/seals you need the advancement 'adventuring time'. 'Adventuring time' needs the biome 'mountains', which is not enabled in the modpack.

An easy fix would be, to delete biomes from the 'adventuring time' requirements, if those exact biomes can not spawn.

Thanks for the report. I'll see what we can do.