The overwrite happens to me often. It seems to be a cache issue with rig manager.
If you make a new profile sometimes it overwrites the profile you had loaded when switching to profile mode.
I often close rig manager to avoid this but sometimes it still happens. Sometimes it over writes the said profile with the new one and also saves the new one separately so there are two of the new with the same name.
I have reported this to support and was told rig manager was not made to be used with profile mode.