fenix 6 not detecting pool laps/measuring distance?

I did my first pool swim with my 6X yesterday and it recorded each lap perfectly. Did you use a different Garmin watch for swimming before you got the Fenix 6 and did it record correctly? If so then you may have gotten a defective unit and should consider returning it for a replacement, though I would try one more swim first just to see if that first one was a fluke. If you haven't swam with a Garmin wearable before I would suggest making sure stroke detection is turned on and that you are pushing off and gliding for a second or two at each turn. Since the watch relies on that to know when each length is completed that can be a source of error.

Thanks for your response. I was swimming with a Fenix 5 until now. No problem at all. I will reset my Fenix 6, and give it a second try...

Recorded perfectly for me when I tested it in the pool today. Granted I pressed the lap button between each lap.... but it already counted the lap before I pressed the button., 

I had a similar issue depending on the rhythm / kind of swim. Front crawl was ok but for breaststroke it depended on the rhythm. If too slow, no record.

If I stop in mid pool length to clean my goggles, the watch can come to a conclusion that you've passed one pool length, even if it takes a second or two to pass. Also, if I had to change pace drastically due to slow swimmers, the watch might add one or more pool lengths to the sum. I don't think it's a bug. The algorithm that detects one pool length needs some work, but what I'd hope for is a way to edit the distance afterwards, just like in weight lifting.

When I was able to swim without interruptions the distance recorded matched reality.

I had the same problem this morning. I swam for 40 minutes non stop and the distance it gave me at the end was 25m??? Pathetic I'd say.

I swim in a 50m outdoor pool. I swim a very consistent pace each time (I'm trying to improve but pretty much at my max for each length). I do 5 sets of 4x50m intervals with a 2min rest (so 200m then 2min rest and repeat until 1000m swam). 

I've done it 5 times now and every time I get a different distance. It pretty consistently counts too many lengths. It doesn't count too many for every interval instead the first interval will be correct and say 200m. The next then might go up to 300m but I've still only done 4 lengths. And the same for the next and then it normally gets it right again for the last couple. Very frustrating and no way to properly correct it. I can manually amend the distance for the whole swim down but it still thinks my fastest 100m is twice as fast as it actually is. 

What stroke? How fast per 100m?

FrontCrawl - almost always 2min 30sec / 100m