You said you reset the panel but did that include ""reset all grids""? It seems like the wrong grid keeps loading here. If you think Sy_Personalize is in play here might be better to exit MAS, rename the whole file, then when you go back in it will create a brand new empty one. Easier than find the record you need.
BTW, I DFDM delete crap out of there too but usually for screen resizing issues. Side note: Sy_Personalize is supposed to hold:
* F records for screen position, size, and maximized state of the screen
* K records for reports and forms where the Print or Preview checkbox has been set that allows you to keep the report / form open after print/preview