We keep nudging pickup points when our Fairino FR5 setup gets unreliable at tray-to-fixture transfer with a rigid spacer block in a shared tray handling station. The tray looks like it's in the same place, but the grip seems less square. I'm suspicious of all these tweaks.
What should I inspect before blaming the arm or reteaching everything?
Look at the relationship between the workpiece and fixture before contact, then during gripping. Can your existing observations show when the change in angle begins?
Keep a copy of the current configuration and hold off on further coordinate changes. Under the appropriate isolation procedure, maintenance can use the observed rotation to focus inspection on tooling contact, mounting and tray seating.