That sounds like a software problem that some of the EVs had years ago. The workaround was to turn off "dead reckoning". That's the feature where the Sat Nav calculates its position using the car's speed and possibly bearing. Useful when in tunnels or other areas where access to satellites is temporarily blocked.
But a software bug means that it uses this all the time, even when access to satellites is good, so it quickly loses all accuracy. But I think with the EVs, the position would not update at all.
The proper fix (for the affected EVs) was a software update. I would hope that this buggy software never made it to the relatively recent models like the Hybrid+ ones, but never underestimate MG for this type of thing.
It's certainly worth trying turning off dead reckoning. At the very least, it's good information to tell the dealer, and should smooth the way for a warranty software update.