Body classes being lost

Hello, this plugin fit perfectly what I was looking for, and appeared to work properly to fulfill my needs….except for some reason I have not found yet, the classes I enter into various pages disappear after awhile. Not just a few, but all of them. Assuming they are being written to the db, I cannot conceive of a reason for this. I’ve also verified that I’m not being sabotaged by co-workers.
Please help.
Thank you.