Faints on blue BFN on red

I’m curious to know if this has happened to anyone. I got 4 faint lines on blue dye (not evaps they were there almost immediately and they were blue so couldn’t be an indent) but when I tested with red dye I didn’t see any line. I’m gonna wait a few more days to retest but never in my life have I ever been this late. I’m on CD 37 normal cycles 25-30. Even when I was a teenager I didn’t have cycles longer then 30