Another possibility (other than warping) is that the glass surface is not level with respect to the bed washers – one or both of the washers on the right side may be loose. When the washer is loose even slightly, it can tip up a bit from the pressure of the flexible pad underneath the build plate (particularly on the 1.03 (foxglove) version of the Mini). Since the auto-leveling probes touch the washers, a tipped-up washer can result in the Mini thinking the bed is higher than it actually is at that corner.
I’ve found the best way to snug those up is to squeeze bed plate and printing surface together with thumb and forefinger, so that the printing surface is no longer putting any pressure on the washer – then just snug down the screw holding that washer until it’s tight. Careful – it’s easy to strip the threads on the build plate if you over-tighten; just snug down the screw, don’t torque on it!
I’ve found it useful to recheck these washers regularly. Perhaps that’s a sign I’m not tightening the screws enough, but bed plates are expensive, and it’s easy to check for tightness (if you can rotate the washer by hand, it’s loose).
Finally, another easy thing to do is to help out the auto-leveling (whether it needs it or not!) is to manually ensure that the two z-axis are “synced”. This process is described in the alignment instructions on ohai.lulzbot.com – the idea is that in a perfect world, a long move on the x-axis should not require any movement of either z-axis to keep the head level with respect to the build plate; it’s pretty simple to get this very close so I also check this regularly. (Although after the initial adjustment I did, I’ve never seen it change on my printer.)