Radio issue exist?

Hi guys, may I just check if anyone know if it is possible that some hotspots have “radio issue”? I mean I have 5 heltecs and I tested them in the same antena with my mapper… seems that 2 of them that are not witnessing anything they have a terrible RSSI, almost double than others. Again, the test was performed in the same antenna and the 2 that are “dead” are the ones with high RSSI. See cxomparisson between a normal one and a “deaf” one below. Any thoughts?Capture