Using the latest fix to Amidst I noticed that Pillager Outpost possible spawn locations identified by Amidst in Snowy Tundra and Snowy Taiga failed to generate whilst they did generate in all the other biomes. 

To double check I created single biome normal buffet worlds for all the biomes Pillager Outposts are supposed to spawn in, and found that this confirmed my findings.

This is not like the bug where the tower wouldn't generate but the location was confirmed inside the game by using the locate command. In this case the locate command doesn't identify any Pillager Outposts to even exist.