As Northwind says, it’s likely they’ve been bled with part-worn pads in, meaning too much fluid in the reservoir.
I’ve got a set of R1s and a set of RXs and changing pads isn’t an issue. I’d fit new pads and do a full bleed this time, then if the problem is still there come next pad change something else is going awry.
That said I do find them quite awkward to set up perfectly. If your rotors aren’t dead straight they seem to be hard to get them drag-free. But performance-wise they are good.