Hi, interesting observation.
When GE became Cytiva, only the company changed from name and all the Biacore stuff should be the same. That said, I did not ask them.
I am impressed with your 600+ cycles but unsure that it is because the sensor chip (not immobilized) was previously better or that the immobilized ligand is less robust (or something else has changed).
I will keep my eyes open on the next runs and compare them with the old.
Kind regards
Arnoud