The sort row keeps going back, help!


I have a quick question - I keep reoganizing and sorting the rows by "PI Initials" and somehow it keeps going back to the older order…driving me crazy! This is a shared sheet with others and they work on it during the day. Is there a reason this is happening? I asked my coworkers and no one is reverting it back so I'm wondering if this is a glitch or if someone is in the sheet while I am doing this, does it unsave it? HELP PLEASE.