Spirit loss

I’m playing an explorer. I had enough spirit to use Grim feast, Wind dancer, and Herald of Ice and thunder and still had 16 left in spirit. Out of the blue, I lost 20 in spirit and I don’t know how,. No changes in gear. I made changes on skill tree but nothing more. Can anyone help? Any clue?

Just for the sake of ruling out the obvious, did you add a support gem to one of your skills? Some of them come with Increased Spirit Cost.

You saved me bloke. I was desperate. TY a ton, take care.
Edit: It looks like a bug, I removed "Clarity" and "Canibaslim" from the "Feast" and certainly that seemed to be the problem, but I put them on again and oddly enough I have enough and 16 left in spirit again.