Confused

Alexus

I’m 11 dpo today. I took the internet cheapie this morning with fmu and got a bfp. With that same urine, I took this 88¢ test right after and bfn. However, sometimes when I look at it I think I see the tiniest hint of a line and other times I don’t see anything. Could the first test be faulty, an evap (even though the test line has color to it), or could the 88¢ test just not be as sensitive, even though they’re both 25miu? Planning on testing later with FRER. Thanks!