Jarsyl, Dark Age Scion allowing Escape cards to be cast without paying Escape Cost.
OP plays Jarsyl, Dark Age Scion with 5 Mana Open.
Intensity set to 1
In graveyard OP has Fatal Push, Thought Seize and Kroxa, Titan of Death's Hunger.
On trigger of Combat OP plays Kroxa, Titan of Death's Hunger which is 2 CMC paying two mana from their mana pool.
Text on Jarsyl is:
At the beginning of combat on your turn, you may cast a spell with mana value EQUAL to Jarsyl, Dark Age Scion's Intensity from your graveyard without paying its many cost. If you do, perpetually increase Jarsyl's Intensity by 1.
Kroxa's CMC is 2 which is 1+ the Intensity at the time. OP should not have been able to play this Kroxa without paying it's Escape Cost which is 4CMC and exiling 5 cards from the graveyard.
If I were to guess you latest patch bugged escape card, since Kroxa and Cling to Dust, while in your graveyard show in your castable cards with their standard cast. Then the code from Jarsyl triggers to say you can cast a card from your graveyard, ignoring the second half the sentence and allowing players to play their escape cards without paying the proper cost.