Oath of the Gatewatch event Part 1 "Rare" Glitch?

WeaponX71

Just played the event Oath of the Gatewatch event Part 1 and came across two glitches with the last two boss events. The first glitch I didn't catch the actual card, but the second time it was when I was in a duel with "World Breaker". He matched one instance of color that wasn't his own color and somehow played the card "Gladehart Cavalry", with a casting cost of 21, no other supports on the board. First, how is that even possible. One match gives you 21 mana? Then when the card hit the playing field it increased to a 22/22. Even with it's own bonus, that just doesn't work out. Again, no other supports or cards played that round. But even still, that is at least 63 mana needed to even get close to that size. From ONE non-color match.
The first time it was a rare or mythic card, same scenario happened. Might have been "Skysovereign Consul Flagship" as I remember have a lot of 5 damage indicators happen, but it two doubled, and with the same non-color single match. I think the most they got was 8 or so mana, but then poof, something which should have cost 50+ mana is on the board.

Anyway, love the game, just frustrating to see these things happen.

And anyway to keep opponents spells up on the screen longer? Sometimes I can catch which spell just happened.

Thanks,
Mark G