I'm getting really frustrated with first response tests.

Took this test last night at 8 dpo and there is a very very faint line. But that line was also on my 7dpo test. It looks the same, no progression. So this must be an indent line, but both tests I took (at 7 dpo and 8 dpo) were from different boxes I bought. Are first response tests just prone to indent lines? This is super frustrating.