White/clear line

Hi ladies I am new to this as my SO and I just started ttc and I believe I am around 12dpo.  I took a FRER test July 4 and it was clearly negative, no doubt. I took another FRER test this morning with FMU and there was a white line where the second line would be. Has anyone else had this and then a BFP or any idea what this means? I've read a line is a line and I've also read it may be an evap line. Should I test again in the morning? I'm hating the mind games as ice had so many symptoms the past week or so.