After months of use, AppleWatch 3 over-counts laps by 2x

I have been using my series 2 watch for 2 to 3 months to swim laps indoors. I do not do flip turns. The pool is 25 yards. I alternate every lap.. free, Breast and back. The watch overcounts laps by a factor of two. In other words, it seems to count lengths verses laps in terms of numbers although yards are double too. I saw one post where someone posted a screen shot of their workout summary and it actually showed lengths. I have no idea how that can be because I don’t have an option to change laps to lengths. Apple just told me to repair with phone and reset settings on phone. No change. Very frustrating. This is main reason I bought the watch. Ideas?