Game Mechanics: Low level necro pets using double attack

[cavalier]

My level 1 and level 4 necro pets used double attack (they had a weapon equipped). Also tried this with a level 8 necro pet without weapon - it still used double attack and even double bash.

This seems very weird. Is it possible that the pets are not actually hitting twice, and that it is merely a bug in the text output?

Pet slashes a decaying skeletion for 5 points of damage.
Pet bashes a decaying skeletion for 9 points of damage.
Pet bashes a decaying skeletion for 9 points of damage.

However, I also had double attacks with different damage numbers like:

Pet slashes a decaying skeleton for 4 points of damage.
Pet slashes a decaying skeleton for 17 points of damage.