Vvfl on clear blue plus, then "not pregnant" on digital using same urine?

Has this happened to anyone and then they later found that they was indeed pregnant? I took these same tests my whole time while ttc (4 years) and never experienced this? My last pregnancy I took the clear blue plus first and saw a faint but very visible blue line so I took the didgital durectly after and it said "pregnant" this faint line I just got today is a bit lighter than how it was my last pregnancy though? So maybe its just too early? Or something else. But anyways looking for some answers to my question. Thanks for reading! Xo!