I attempted to cast Piercing Exhale, and was able to pay for the green mana by tapping a forest. I was unable to tap my mountain for mana despite clicking on it many times. I also had trouble when clicking on the creatures (targets of the spell), but they eventually worked after many attempts at clicking. I tested my mouse and believe it works consistently.

Also, I had used Hold Full Control previously and it seemed like "auto pay" didn't turn back on.

I am not sure how Arena handles the additional Behold cost, like when does it ask if you wish to pay the cost? Maybe it only asks if you actually have a dragon to behold, which I did not. But I am pretty sure I was in the process of paying the mana cost and that I succeeded in paying the green mana, but not the generic one.

Playing on a Windows 10 operating system.

Game version: 2026.59.30.12801.1279316

Frustrating to lose a game due to this when I had just paid to enter a sealed tournament. Money back perhaps?