Does anyone know why my conditional formatting rules sometimes mess up and automatically change by themselves?

I have a rule that applies to A2:B200 however every few weeks I’ll see that the conditional formatting doesn’t get applied right and I’ll open the formatting rules and find it looks like “=A$21$B$67$B$63$B$69$A$71$A$72$A$74：$B$200” when it was set to “=$A$2:$B$200”.

Does anyone know why this happens and how to prevent it from happening in the future? I am using the latest version of office 365 and my document is saved in OneDrive.