FRER evap line???

Kayla • Married & we had our perfect baby boy on 03/21/2015, Pierce Huntlee. He was 7lbs 10oz, & 19.5 in 💙
Is it possible for FRER to have an evaporation line? I'm hearing no, but seeing yes! I am 10dpo, and tested this morning, I got a grey line! Yesterday I tested on dollar tree test and got a very faint line.. Not sure what to think of this? 
10dpo? Evap?