Also if changing brands of litter do so gradually, by mixing the current and new brand together at first. (cat-health-guide.org)
I thought it was the type of litter at first, so I tried 4 different brands of litter before I realized maybe it was the type of litter box. (chewy.com)
If you suspect one or both of these things could be true, give a new brand of litter a try, or upgrade to a larger sized litter box. (thesprucepets.com)