I don't know if I've had that issue or not. I don't think so. I know the older one has had issues with the rail causing it to loose lock with the handheld unit. I've witnessed a few scrubbed launches because of that. I usually watch the track of the rocket from the table to the RSO and then to the pads. If it looses lock then, I don't know. The Rocket Locator app continues to show the rocket location if it has a lock or not. Once it's launched, it has worked great.
I haven't had any problems with it and was sure glad I put it in my L3 bird today. I wasn't going to because it's so big and only going about 5500 ft. I wasn't going to loose sight of it. But after the first rocket went off the away pad and I saw how strong and direction of the upper level winds, I put it in. Ended up 3/4 mile away and in a 40 acre corn field. The Rocket Locator had downloaded the satellite images so I had a good visual of nearby landmarks. Ended up walking right to it. We brought the receiver along this time and it was only off be less then 5 ft. by the time we got to the rocket.