Cards in hand disabled while tapping after match [Investigating]

After matching 3+ gems to fill up cards with mana and play them, cards in my hand are sometimes disabled similar to using a card with the Flash mechanic on the opponent's turn - i.e. manually opening the hand panel and tapping the icon to gray the card out from use.

This behavior only occurs on the left side of the screen, not the hand itself. I have only noticed it while tapping on the board to acknowledge the current card being played.