The tool bar displays the position of the current record in the current found set's sort order. This can be a completely different value than a serial number field in your current record.
Is your record order based on a sort and are you changing data in that field and does changing the data alter the sort order? I've seen report views where editing a record will cause it to move to a different position in the report and creating a new record on commit will move to a new position in the report view.
Although I have had issue too, (especially when the sort includes the date that is being updated), the issue I experienced was not based on the sort order. It was very bizare. I have not experienced it again for quite some time. My latest guesses are that either the file was somewhat corrupted - and now fixed, or my latest thought... On FMgo if you change the app without closing the file, the next time you open FMgo it asks if you want to pickup where you left off, well, it is possible that I had sync'd to computer, updated, and re-sync'd to iPad in that time, and (not knowing how FMgo deals with memory issues) perhaps FMgo is attempting to utilize the "saved state" it had when the application closed with the "new" data set.
Not sure how I was doing before, but now I make certain to deny "starting where I left off" after syncs, and I haven't had the aforementioned problem in quite some time.
I appreciate all the responses I received on this issue...