Disappearing Mana Crystals

Unknown

Has anyone else had issues with disappearing mana crystals? I was working on Seismic Elemental and completed the first challenge for 8 crystals bringing my total to 400. I healed my planes walker and completed the second challenge for 15 crystals but at the end of the challenge my total was 329...I lost 86 crystals somehow. I've tried closing out of the game and reopening it but it's still reflecting 329.

I can't be positiv but I'm pretty sure I've had this happen before which is why I started tracking my crystals so closely.