Tridents or arrows shot through lava sometimes don't catch fire

The Bug:

Tridents or arrows shot through lava sometimes don't catch fire.

Steps to Reproduce:

1. Build the setup shown in the attachment below. setup.png
2. Stand on the diamond block and throw/shoot multiple tridents or arrows through the lava.
3. Take note as to whether or not tridents or arrows shot through lava sometimes don't catch fire.

Observed Behavior:

Tridents or arrows sometimes don't catch fire.

Expected Behavior:

Tridents or arrows would always catch fire.