Pregmate false negative on expired test?

Just curious. Has anyone used an expired Pregmate test and it been accurate? I used them without realizing they are expired. I was getting positives on them and then I got one that was negative. I didn’t realize they were expired until I got a negative result. I also took a FRER regular test and a FRER digital (which were both positive). When I got the negative on the Pregmate test (after having positive Pregmate tests) I became concerned. Is the negative result because of the expired test or could I be experiencing a chemical? I’ve had a chemical before and realized I was having a chemical when my lines disappeared. I’m scared that’s happening to me again.