Both Mindstars destroy during routine fight

[joniii]

I was fighting routine monsters on level 39 of insane. The next thing I noticed was that both my mindstars had been destroyed. Is this a bug or something else?

Details:
Character Adventurer with mostly oozemancer abilitiies plus gem ability (plus 20 to all stats is not bad).
Mindstars were great ones from the vault (something like Eyal and Nexus of the Way) which I had been using since around level 23.

P.S. It was a great character. I was routing everything.

[HousePet]

Are you sure you didn't just switch to your off set?

[joniii]

Boy do I feel stupid! You solved my problem.

Thank you very much.

P.S. I had forgotten about the off set because I have not used it in a long long time. I must have inadvertently hit the Q letter. Thanks again!