There is currently a bad interaction between FARL, Alien Biomes, and Dectorio. If Alien Biomes is installed, Dectorio makes the alien biomes tiles that are user placeable. As a result, FARL considers all alien biomes tiles removable, and then does so.

To fix, edit line 953 of FARL.lua, adding a check for 'dect-alien-biomes':

            if (toPlace and toPlace ~= "landfill" and toPlace ~= "bi-adv-fertiliser" and not string.starts_with(toPlace, 'dect-base') and not string.starts_with(toPlace, 'dect-alien-biomes')) and not self:is_protected_tile({ x = x, y = y }) then

That didn't format well. I'm going to repost, breaking up the lines:

There is currently a bad interaction between FARL, Alien Biomes, and Dectorio.
If Alien Biomes is installed, Dectorio makes the alien biomes tiles that are user placeable.
As a result, FARL considers all alien biomes tiles removable, and then does so.

Fix will be posted in next post.

line 953 of FARL.lua:

if (toPlace and toPlace ~= "landfill" and toPlace ~= "bi-adv-fertiliser"
and not string.starts_with(toPlace, 'dect-base')
and not string.starts_with(toPlace, 'dect-alien-biomes'))
and not self:is_protected_tile({ x = x, y = y }) then