In a game of Historic Brawl I had my commander, Sythis, destroyed multiple times due to Displacer Kitten's ability. I had valid responses to the Reclamation Sage's trigger (as you'll see I had a Selfless Savior on board and a Boon of Safety in my hand) but it wouldn't let me respond to the Reclamation Sage ability when I should have. It's not clear in the attached pictures, but I didn't have the "Pass until end of turn", button pressed.