Cat does not scare

When a crapper came over at day, I went over to a cat, but the cat did not scare the mob. Instead, the mob turned into TNT, causing the cat to die.

Expected behaviour:

The cat scares away the mob, and the mob does not explode.

Observed behaviour:

The mob explodes and kills the cat.

Notes:

Am using a texture pack, however this happens without pack. This happened on a realm, but has also happened on singleplayer.