Lightning rod crashing during Farmageddon battle in Mutant Battle Arena

Verification builds: Release 920093 - 1.5.0.3 BETA
Summary: Using the lightning rod in Mutant Battle Arena against Farmageddon causes crashes when spamming it.

Repro Steps:

1. Download Mutant Battle Arena
2. Break the sign and put a button where the boss battle option is
3. activate boss battle mode
4. give yourself a lightning rod with /give @p fishing_rod
5. fight farmageddon
6. spam the lightning rod

Observed Results:

1. In rare occassions, the game will crash, can be hard to reproduce
2. I suspect it is occurring when the lightning is being summoned on the same tick that the wither skull is being destroyed and summoning a wither pig.

Expected Results: the game shouldn't crash

Impact: Not good player experience

Debug attached, Video