yeah, grass mats can be confusing for litter training, as there is hay in their box too.
My buns NIC condo has wood levels, covered with peel and stick tiles, with fleece stretched over the levels and clipped in place with binder clips. Bertha tends to pee on soft things too, but I’ve found that she doesn’t if it’s stretched tight enough.
The bottom level is wood, with “VCT” tiles held down with double stick tape. The VCT tiles are a bit more grippy than the vinyl, so I don’t have anything over them. My buns haven’t had any issues jumping into their litter box with the VCT tiles.
You could also try card board over the tiles. Easy to replace and would give more traction.
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The answers provided in this discussion are for general guideline purposes only. The information is not intended to diagnose or treat your pet. Seek the advice of your veterinarian or a qualified behaviorist.