Uti’s???

I’ve had many utis before but this one i’m confused with...I just had routine blood work work done and a urinalysis and they found the bacteria in my urine was high so they sent it for a culture and it turns out I have a uti. I have no symptoms at all besides some cramping in my kidney are. I’ve always had horrible symptoms with utis so I’m confused. I’m gonna take the antibiotics I was prescribed anyways but I was wondering if anyone else had this issue before?