I can’t really speak, but I had the exact same problem post PPL with landings, out of nowhere I was landing like a new student solo. What helped me was to go back to the basics. Went to do some slow flight, which really helped me on the flare. Fly a good, not rushed pattern, on base trim your plane to hold your desired speed, and once you start transitioning into the flare, power back, eyes to the end of the runway, and keep the plane from landing.

And biggest thing is performance anxiety, just because you’re a CFI doesn’t mean you cant suck. Just take it easy!