We haven't heard of this happening before. There isn't much that is different in the app between using the X3 camera and the X5 camera.
The camera feed will blink when an image is taken. Delayed and pixelated or distorted video certainly shouldn't be happening. This sounds like a hardware issue since there isn't really anything Map Pilot can do to make the signal strength go bad.
Are you making sure that your antenna are pointed at the aircraft properly to maximize the signal strength?
Are the flights that have good signal and using DJI Go done in the same area? We have seen a lot of signal degradation due to interference.
If you have access to the faster iOS device you might want to try that too. The Mini 2 is the absolute lowest model we support and it might be causing issues.