Pandas will not breed.  I have all the requirements met:

• I found both my Pandas in a jungle biome.
• I put them in a fenced enclosure.
• I surrounded them with 20+ growing bamboo
• I fed them over a stack of bamboo and a few cakes.
• I tried removing the enclosure to see if they breed
• Still no breeding/babies!

Secondary note:

My first two pandas would not breed.

I found new pandas in a new location, and they will not breed.

I went on my friends world, they have pandas, they gave them bamboo and they breed!  I fed the same pandas and they will not breed!

*I also noticed that the pandas seem very buggy. Sometimes they are stuck in animations, they are unresponsive, and they often do multiple eating animations with one bamboo and stay stuck supine.  Sometimes they are even frozen.  I even get disconnected from the world occasionally when interacting or near the pandas...