I don't believe it has any reflection on any unsafe practices; it's not worded brilliantly. It's more that engines get swapped around the fleet during their lifespan with an airline and when the aircraft are returned to lessors in an orderly fashion, the correct engines are back on the correct aircraft for the handover. However, with the airline suddenly being grounded overnight - engines are not on the correct aircraft, so need to be swapped before they can be returned to the lessors.
Appreciate the insight from those who responded, thanks. I work in IT and a lot of the "tin" humming away in Data Centre's these days is leased. Same kind of things go on (bits get moved around, robbed and ultimately replaced etc).
I saw on a FB group used by some staff at SOU that a few of the Dashes there have had some work done (there was a pic of one hangared, I think in the Signature hangar, which I was surprised to see), so I guess things are starting to move?