I sometimes get drop-outs, which seem to be a sign of a sensor which is later fail. It doesn't tend to happen very often though (for a given sensor) it's more often the case that it drops out for an hour or more and then comes back to life, or not!The signal loss is driving me mad! Never been good since I first started using the sensors back in January of this year but now I’m recording signal loss on average 14 times a day and through the night it just fails to connect! Really frustrating that what should be a life saving device isn’t working properly.
Are your sure your frequent signal losses aren't to do with your phone (I assume you're using a phone?) and the app being killed when it's in the background, which is something I understand can happen quite often at night. With Android there's usually a way to both mark an app as not being killable, and also not subject to battery controls (though it depends on the version of Android and the flavour of the UI from the manufacturer.)
If your failures are in fact the sensors (e.g. you've done BLE scanning to see that the sensor isn't transmitting) then that's interesting as I've never encountered a sensor which does that.