Arranging Reading Order in Acrobat Glitching Out

I am accessibility tagging a PDF with a lot of form fields. I have all the Accessibility Tags in the correct order in that panel, however the reading order numbers are all over the place in the Order panel. For example, one of the first headings is numbered 147, and I need it to be 8th. When I drag that tag up the list, the whole Reading Order panel flashes and glitches for a second, and then the heading I tried to move is either in the original location (147th), or some other random number/spot on the list. Is there a more exact way to change reading order other than using the drag and drop method? Is the flashing reading order panel an indication that there are too many form fields for Acrobat to handle? Any advice on this would be appreciated. I've attached a screen recording of what happens to the reading order pop-up panel when I try to drag and drop in the fixed Order panel.