When there is a block above the pitcher pod, it can still grow, resulting in only the lower half of the mature pitcher pod remaining

When you use a bone meal on a pitcher plant that is below another block, it can create an age 2 pitcher plant that is missing it's top half.

What I expected:
Pitcher plant cannot age past age 1.

What happened:
Pitcher plant became age 2 and lost it's top half.

Note that this takes a few tries.