Battery Charge Fault - Stop the vehicle

[Superelastik]

This first appeared about  when tge car was around 8mths old. Citroen Assist visited, checked battery and found tge charge rate was good and tge fault cleared itself.  A visit to the dealers unsurprisingly could find nothing wrong.
About 2 weeks ago the fault light reappeared,  somewhat reluctantly and dye to my location I ignored it and drove for around 3 miles before parking for about an hour. On returning to the vehicle I restarted tge car and and tge fault was still present.  I drove off and the fault cleared itself about a mile later.
Yesterday on the M25 the fault light reappeared.  I stopped after a few miles and checked tge charging rate which was fine. I stopped and restarted engine.  Fault light remained on. But then cleared itself after driving a few miles.
Has anyone experienced this problem?
I suspect when I go back to the dealer it'll be no fault found again.

[Leonberger]

I suspect that it may be just a warning light gremlin. We had a similar situation with our C4 Grand Picasso, where the low oil warning light would come on from time to time. I would check the oil, which was fine, and on the next journey there would usually be no warning light, though occasionally it would come on again.
This happened for a couple of years. I would check the oil if it came on on the next journey, but otherwise ignored it. The oil was never too low, or too high!
Such gremlins are pretty much impossible for the dealer to find, since if there is no malfunction when they check, there is nothing to find.

[Superelastik]

I suspect you're correct. But less than ideal and certainly doesn't inspire confidence for long journeys.
But being positive, at least it doesn't put the car into limp mode!

[Sol]

My B9 has started doing this, happened 3 times so far, it stops charging the battery when it happens (checked with multimeter) and lasts about 2 full minutes, then starts working again.

U1400: LIN network fault, Alternator.

Looks like it's going in for a new alternator soon, before it packs in completely and leaves me stranded.