It seems like this is happening with all GWA2s so not specific to my unit. I've been using the Gear Sport for the past 2 years and have been religiously running, so I have a good benchmark.
Picked up GWA2 on 9/27. Had 2 runs with it so far - I've done both courses multiple times with the Gear Sport.
Run 1: Neighborhood loop (4.85 miles) - distance is accurate so I thought GPS was working. However burned calories was 370 calories. There is no way a 165 lbs male running 5 miles at a speed of 7 min/mile burns only that much.
Run 2: Running Track (3.5 miles / 14 laps) - if you look at the post-run map, it is clear that the watch is all over the place with the GPS coordinates. With the Gear Sport, it outlined the track oval quite well. With GWA2, it almost felt like the "high GPS accuracy" setting was not even functional. Also calorie count came in at 307 calories. Gear Sport used to report 475 calories which is much more in line with the treadmill.
Also, this exact issue seems to have other journalists noting it as well:
Come on Samsung... the product is called Watch Active 2. It is supposedly made for fitness/health tracking. That is the one thing you cannot get wrong. And you had it near perfected with the Gear Sport... can this be fixed with a software update?
I have had the same problem with my Watch Active 2. The watch does not measure distances reliably during Walking workouts. I track I regularly walk is 3.21 km measured using Google Earth. One day my watch will measure the distance correctly (3.21km) and the next day it will measure the same walk as 2.6km. That is a significant discrepancy. For a watch that is advertised as a fitness watch this is totally unacceptable. If there is no fix scheduled soon I will advise people not to buy this device.