Previously unlocked level suddenly unplayable?

Hi guys.

I came across a strange glitch today. I have 100% on chapters 1 through 4, currently working on 5. When I went back to Salt Factory to improve on some scores, I found my 3-1x to be unplayable. I'd hit A while standing on it and nothing would happen.

Obviously it was unlocked since I have A+ on the light world version, and it even listed my best time on the bottom right. Luckily it was an easy level, so I just replayed 3-1 and reunlocked it. It was then playable again. I also noticed my best time had changed to 60.00 for some reason (can't remember if that was on the light or dark version though). I hope it hasn't happened to any other levels, or that it will affect my overall percentage as I'm nearing 100%.

Does anyone know what this is about? Thanks in advance for any help.