Futer Teammate Forfeits on Time After I Play Winning Move

Is this a bug or something?

https://www.chess.com/variants/custom/game/29377929

Futer has a reputation for thinking a little then playing decent moves, but here Futer lost on time after thinking for around 6 minutes and 40 seconds. I (Green) just played camel checks Yellow, and afterwards I am certain to capture the king. However, my teammate Futer (Blue) thinks forever, perhaps unable to search for continuations. The opponent Futer for Red does not to have any trouble. What is happening?

Futers don't think   They make their choice instantly and then wait for a few random seconds.

The futer here got stuck/crashed, it's a bug. It happens in custom games sometimes

Ok, so basically what I'm concerned with is whether this will happen every time, or if this is just a small fluke. Will the Futer crash every time in this position, or is it that I was unlucky?