Ah I wasn’t aware of this, must have been ill-informed at somepoint along the line.
Did however hear from a driver today at Notts that the reason why 222104 (and eventually other 222s) have been pulled from service so early for ScotRail is that the 222s have been sold and technically are no longer are owned by EMR, however due to the delayed release of the 810s they have been told they can keep the 222s for a bit longer, however as soon as a 222 gets brought in for heavy maintenance (which is what happened with 104), it gets nabbed by the leasers. The driver also said that the usual number of engines that a 222 runs on is 3, which is one more than the boundary of 2 that needs to be met before the unit is pulled from service (however the unit he was driving, 222017, had all 5 running miraculously)