Fill & Sign seems to create a lot more than one text box in same location

I am trying to use Fill & Sign to fill out a very long (28 pp) form.  The form was clearly not created by someone familiar with Adobe, even thouogh it's a PDF.  But that shouldn't matter.  I was able to fill one form with only a few difficulties, but made the mistake of explicity Saving, hoping not to lose my work.  That, of course, locked the file, so I can't continue editing it, and I have to start my whole 28 pages over.  This would be frustrating enough, but now I seem to have to pull 5 or 10 or 15 extra text boxes out of the way to fill in even one!

1) Click on Text Box on tools menu to the left

2) Move mouse to spot on form where I want to type something, like a name

3) Type 3 characters, and then cursor movement stops.  A drop down box of choices may or may not appear, but if it does, choosing something does not have any effect.

4) Suddenly, gray "Type Text Here" appears, over the 3 characters I've already typed.

Through trial and error, I've discovered that this "Type Text Here" is in a new box, directly over the box I was typing into for 3 characters.  I can move this box.  When I do, the "Type Text Here" changes from gray to my typing color.  But, there is now another one in the original location.  The first time this happens, I have to move 2 or 3 boxes out of the way, and then I can continue typing in my original text box.  The second time, it's more like 10.  I haven't made it through a 3rd time.

This is not from me clicking in the box to try to continue typing.  I thought of that - that each click might be creating a new box - and now I simply never click an additional time.  I move the box just by hovering the mouse until the movement arrows appear.

So, this appears to be a bug.  But it does not appear to be a common bug, because I don't see posts all over the place here about it.

Any ideas how I can stop this behavior and get back to filling in my 28 pages that are now overdue?