Vvvvfl that went away after timeframe?

Has anyone had a vvvvvfl that showed up within the timeframe, was visible for at least 15-20 minutes after the test was taken, then it went away? I tested this morning and had the faintest of lines, but I don’t think it was an indent due to being able to see a bit of color. It looked like that from the 2 minute mark, then of course I continued to stare at it for like 20 minutes. Then I went to run of errands and when I came home it looks negative? I know there was a second faint line. I’m just curious if this has happened to anyone else, it was a FRER test. I’m going to test again tomorrow and see. But now I’m second guessing myself and I was so excited