Faint line or indent?

I’m 10dpo and this morning I took an FRER, definite faint line showed within a minute and stayed there. I couldn’t believe it and tested again with another FRER, another faint line showed up within a minute.

I bought more FRERs later today so I can monitor line progression. I was going to take a test this afternoon (I’m inpatient) and noticed it had an indent prior to me using it. I then opened all of the FRERs and they literally all have indents. I’m now worried that my two tests this morning weren’t really faint lines. Thoughts?

Do I bother using those FRERs or are they faulty? Not sure if bfps can come through when there’s an indent.

Here’s my two tests from this morning: