This is a strange one Don. If it kept time before and all conditions are the same ie: escape tooth count, pendulum, bob, leader, suspension spring or any changes in the suspension as William suggested then I’m still leaning toward skipping escape wheel teeth. An out of round escape wheel, bent escape arbor pivot, or broken tooth tip or tips can result in skipping. You can check for out of round by removing the weight and then the anchor and advance the train slowly by hand while watching the tips of the escape wheel teeth. You can use anything as a visual reference. Another thing, and this is a long shot, is one of the wheels in the time train from the center wheel up to the escape arbor may have a broken, bent or topped off tooth or teeth. This will cause the train to jump ahead to the next good tooth which will jump the dial train ahead. Also a badly bent pivot somewhere in these same time train wheels might cause wheel teeth to skip ahead but will usually stop the clock when the high side rotates around and engages the pinion. But…maybe?
It’s late so maybe a good nights sleep will bring us some fresh ideas in the morning.
To productive dreams!