I have had the same experience with my skimmer (Bubble magus 220CS). For the first year that I owned it I found that it did this at least once or twice a month and sometimes once a week! It was extremely frustrating and I think I posted about it a couple of years ago. I was about to throw the skimmer in the recycling bin and get a new one because I was so PO'ed. Then I got busy and ignored it for a while. Fast forward a year and I came to realize that a year had passed without it bubbling over once. Then I further realized that for the past year I had stopped using filter socks. Incidentally, I just started to use filter socks again last week to try and clear up my water column and guess what??? Yup, my skimmer cup overflowed last week
The strange thing is that it doesn't do it all the time or with every filter sock change, just with some. I clean my filter socks in the washing machine without any detergent. I suspect in my case what is happening is periodically there is detergent or residue that gets onto the socks perhaps because the previous load of laundry was too full or not full enough, thus not allowing a complete rinse from the rinse cycle. Keep in mind also that it may not be a specific chemical, but rather a certain chemical composition. Perhaps filter sock changes the ionic balance of the water in some way?
So now what I do is dial the skimmer down whenever I put a new filter sock on. I can usually dial it back up within 24 hours. I don't like using filter socks though so long term I won't be using them. I typically just put them on for a couple of days if I've just done some major scrubbing of the glass or rocks.
Anyway, this may not be what's happening with your skimmer but it definitely affects mine.
The other thing that will cause your skimmer to overflow is new epoxy. Although I suspect you'd know right away if this was the case, which it doesn't sound like.
At the end of the day there are a lot of chemicals that can cause your skimmer to overflow like the two I listed above. There may be a tonne of others that you introduce from food sources, your hand (hand lotions, soap, etc). Perhaps a weeks worth of putting your hand into the tank with a certain soap or oils from our skin allows your tank to accumulate enough chemicals to cause your skimmer to go bonkers.