I had (thank god no more) a Fenix5 replaced for water leakage inside, and now, recently, the new one completely died after the first open water session of the year...
On top of it, it never caught properly the GPS signal while OW swimming, I had to rise the arm above water for 30ish seconds to allow (at least) to catch the signal once I was in the farthest spot (embarassing, isnt it?).
Anyhow, long story short, Garmin never replied to my complaints (I was a Garming fan) and I got myself another sportwatch (100€). No more arm over the water anymore to catch the signal, precise tracking while OW swimming and, no water leak inside!!! it was so satisfing seeing the swimming distance increasing while training, I was not used to that anymore...
Just to conclude, seriously this watch passed the tests for 5atm underwater as they claim????? if yes, I want to see the data... I really think that, for these obvious reasons, this watch is not suitable for OW swimming and that the claim that it is, should be removed from its described fetures.