One key on my midi keyboard suddenly functions as CTRL+Z instead of the note

I was composing music just fine until today when I went into note entry mode with my midi piano keyboard and every key works just fine except one now. When I hit F, specifically F5, on the piano keyboard in note entry mode, instead of putting F (let alone any note at all), Musescore 3 now receives hitting this key as CTRL+Z and simply undoes whatever I did last. I have tested and tried this in multiple instances. I have tried restarting my computer AND the midi keyboard. I have tried uninstalling and reinstalling Musescore 3. None of it has worked. I know it's not a computer problem or a midi keyboard problem because I also tried it in Sibelius and that same key and all others work just fine in Sibelius. It's Musescore 3 that's the problem. Please help me fix this or else there's no point in using Musescore 3 anymore for me. May as well just switch over to Sibelius permanently... unless someone can help me fix this.