Wandering trader can spawn on bedrock

Wandering traders can spawn on bedrock, which shouldn't happen considering bedrock as nonspawnable block.

Expected results: Wandering traders shouldn't be able to spawn on bedrock

Actual results: Wandering trader can spawn on bedrock, unlike any other naturally spawning mob

How to reproduce:
Make a big bedrock platform/clear enough blocks using /fill comand to have platform made entirely of bedrock 90x90 blocks big.
Stand in the center, wait until a wandering trader spawns on the platform.