Can a FRER line disappear?

Melissa • Wifey 8/6/16👫 Mommy 11/18/17👩‍👧 Started TTC#2 September 2018

Hey ladies! I posted a picture earlier of my VFL and many of you agreed that you saw it and it was there. (Pictured below)

That picture was taken after 3 minutes but within 10 minutes of taking the test. An hour or so later I went back to the test and it seems like the line has completely disappeared?? (Pictured below)

Has anyone experienced this before? I plan of retesting tomorrow morning with my FMU but talk about getting excited then getting slapped in the face lol. Help?!!