Bastion remnants will ** only generate on previously ungenerated terrain, so if you have previously visited that location in 20w15a they will not be there. To find them you need to either make a new world in 20w16a or load new terrain in the nether.
This is an issue on IOS as well
i too have this same problem
This is also occurring for me, as well as them spawning inside blocks quite often
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on minecraft feedback when i posted about doggo's sheilds and foxes