I've only have this happen to me when I've been using the same preset for two different accounts and then crashing and logging into my secondary account, it then deleted the preset for the main account without much trace of why.
I'm afraid I do not have a solution either, but maybe try to have 2 different preset folders and preset_3 and preset_4 for example, where they have one each if this is your case. Shouldn't really matter to be honest, but I had the issue 3 times and every time from switching between accounts. I haven't had this issue for years.