Bear in mind I use FCC mode but something I've noticed about having a low signal indication, there are times when you can push 100s of meters at that level and then times when it will lose signal soon after. The signal interference in the area, not just from other wifi and cell towers but also buildings, trees, landscape etc and even the air/weather plays a big part in range and how quickly the signal degrades with distance. Also when you get out there near the end of your range the act of turning around to face home can cause the craft to lose signal as the internal antennae change their angle to the RC. One tip to help prevent that from happening is to pitch the AC backwards towards you for a distance until you have at least a couple of bars showing before turning around to come home.
Losing signal is generally something we all try to prevent and avoid as pilots but if you do have this happen it helps to know there's a very high chance the bird is going to come home provided your home point and RTH altitude are set correctly, one of the beauties of having GPS. I started out with non gps drones and if you lost signal there was a high chance you lost the bird.