Very rarely, the new cave generation exposes bedrock after it was supposedly a fixed bug in 20w07a.

To reproduce
1. Load a creative world with the seed "-6688602363726602321" (Only place I have found this bug in natural terrain generation)

2. With cheats enabled perform the command "/tp (Username) 7704 -59 -10050"

3. After teleporting there, you will see that bedrock is exposed in the natural generating cave