Pregmate strips?

So I already got a bfp on FRER and a digital but I have a package of pregmate strips I wanted to track the line progression with (previous miscarriage) my line progression with the 3 FRER’s I took are great but you can barely see anything on the Pregmate strips. Has this happened with anyone else? I used them with my last successful pregnancy and they worked great but this time, not so much. The FRER’s are 9, 10, 11 dpo. The Pregmate is from 10, 11 dpo. Digital is 11DPO as well. Thank you!