Strange Cascade "skip" [BUG]

What you were expecting to happen, and what actually happened?
I have been playing my endless loop team (transform all X gems to Y gems), and I came across a very strange, yet extremely rare bug. The transformed gems supposed to be a cascade of 4 “overslept” a turn - staying on board. Once the enemy decided to move a gem - the gems “woke up” and counted towards enemy turn.

What are the steps to make it happen again?
I have absolutely no idea. This happened only 2nd time in my life and I play a lot. When it happened 1st time, I thought I saw it wrong or my eyes were too tired - misunderstanding the board.

There also was a very brief FPS freeze before the bug happened (around 0,4 sec. long) and the last time it happened was from turning Brown Gems to Blue ones as Terraxis. Vertical Cascade of 4 gems, most upper column, second from the right.

(I doubt it helps, but every single piece of information can turn up to be useful).
It’s not a serious issue, it’s extremely rare, given how rarely it happens but making a note of it seemed like an appropriate course of action.