This issue has already been reported here, and I could reproduce it
I don’t know if this has officially been reported to Steinberg (@MartinJirsak, do you maybe know something?), but I would also recommend opening an official support ticket in any case.
The Groove Quantize presets and preset management system as a whole needs an overhaul IMO. Your issue might be a good excuse to start working on that. Not trying to hijack your thread though, so I’ll leave it at that.
What I’d ask for is a favorites list per project or somehow pin quantizations to the top per project.
Many of us have long list of custom quantizations but only use 1 or 2 per project. It can be difficult to remember the quantizations used later down the road.