Stumped on auto populate staying in a combo box

This is embarrassing. I’ve been building databases since 1999 and now I’m stumped

I have an MS Access database with a combo box that is used to select specific records.

These records have two particular fields. A primary key named “Track” and a value associated with it called FTitle. Track is a numeric field and FTitle is text. FTitle shows the job title.

I had this working beautifully on a database for six years. Go into the combo box, start typing in the FTitle and it would auto populate with an FTitle name. I've checked everything. Auto expand and everything else

Two things are happening here. I cannot get an autopopulate combo box to work. It works when I make it. Then when I reopen the form it stops working.

I tried to add options to the existing front end which autopopualted perfectly. It seems that when I added a subform to the form the combo box auto populate on stopped working.

Any advice??