Are you tracking your calories? No matter how short your window, if you’re not eating below your TDEE you will stay the same or gain.
You may have also just stalled for a bit, and in a week or two, a bunch will come off. I lost 60lbs in about 6 months, sometimes it was steady, sometimes a bunch would come off at once. I think a lot had to do with my period (I always gain 4-5lbs right before, then the morning it starts be down 6-7), and bloat as I never tracked on weekends. Stick with it, you’re doing great!!
Your body may be hanging onto your food because you are not eating enough, thus it thinks it’s going to starve to death. Trying increasing what you’re consuming and changing up your fasting schedule. Change your fasting & eating windows so your body never knows when it is going to get fed next and will start consuming fat for fuel & make sure you’re consuming enough food so your body doesn’t panic, but not so much food that if you weren’t IF, you would obviously gain weight easily. I always change my eating & fasting windows & have had immense success with it. I don’t count calories and if I feel like eating a lot one day, I will & if I feel like only doing OMAD another day, I do that too. I’ve lost 31 pounds since 12/7 doing it this way & being disabled, I’m largely sedentary.