How to reproduce:

1. Create flowing lava incased in a block such as glass blocks
2. Create a pocket of air surrounded by glass on top of the flowing lava
3. Summon experience orbs using a command block

Observations:

1. The experience orbs bounce around without dying in the lava
2. The experience orbs seemingly go through the block but does not actually
3. When the lava source block is removed, the experience orbs die as usual