This is a constant niggle that I have not solved.
My team has several workbooks for tracking documentation. I have set them up
as Lists for ease of entry and analysis.
I've set Freeze Panes to show the first row and top column. Nothing is
protected, the workbooks are not set to shareable. They are not huge: the
biggest has about 1000 rows and 16 columns.

If I work on a workbook by changing, deleting, adding, re-ordering,
filtering records, refreshing pivot tables (on non-frozen sheets), and reopen
it, the freeze-panes probably still work; but if I open it again tomorrow
after colleagues have done the same sort of work, I may or may not find that
the freeze has thawed. I know I said 'filtering' there but I always Show All
before finishing, and usually the freeze stays when I do this. My colleagues
deny changing these settings and have noticed the problem too.

Is this a feature I must accept, or am I missing something silly?