Pandas no longer spawn in Bamboo Jungles in normal worlds

This has existed in the experimental snapshots and has carried over to 21w37a.

Pandas do not seem to spawn, at all. Going to a Bamboo Jungle, in my experience, doesn't even yield one panda. They simply do not generate. If anyone else has encountered them getting even one must be extremely, extremely rare because in the dozens of worlds I've created I have yet to see one in the world generation overhaul. 

 

Expected Result

Pandas would spawn as normal