All of the following happened in September 2024.
My first 955 Solar (7EG015180) worked fine for 2 years until barometer sensor failed. According with Garmin Support Spain it was due most probably to chlorine damage during swim activities (I swam for 4 to 5 times per week last year). Consequences were that altimeter displayed values all over the place like -7000 meters with me at ~1000 meters high, no calibration or hard reset fixed the problem. I got a replacement after an RMA.
My second 955 Solar (7EG052027) after RMA had problems since day one, compass very laggy, HR not working for much of the time, by the end not even vibration was working when alarms were triggered. BMX / WHR / Sensor Hub showing versions 0.0.0 / 0.0.1, strangely sometimes it recovered by itself, versions were displayed correctly and sensors would start working for some time (hours maybe). After update 20.29 problem continued so another RMA.
My third 955 Solar (7EG052041) arrived yesterday. It looked fine, responsive, watch updated to 20.29 using Garmin Express as soon as I received it followed by Hard Reset to start fresh, connected to Gamin Connect in my Phone everything was looking fine. I woke up this morning, tried to check the time by clicking backlight nothing happened, turn on bedroom lights to realized watch freeze at 01:29am. After a soft reset by long pressing top left button I would say battery dropped by at least 30% between 1:29am to 8:00am.
This is frustrating, maybe I am getting reconditioned (bad) units through RMA which could justify why the watches are having problems since the start.
Long term Garmin customer FR405, FR610, Swim, Fenix 2, Fenix 3, Fenix 5, FR945, FR955 Solar (besides Edge 810, Edge 840, Rally RK100 and maybe something else I'm not remembering).