Today, I reached out to Garmin Support about my Vivoactive 4 watch; more specifically, about its recording of steps.
For nearly 250 days now, my partner and I have been committed to getting our 7500 steps goal each day. I have the Vivoactive 4, and she has the 4s. We purchased them ~11 months ago.
Currently, she has a related ongoing support case,
For both of us, in the past few hundred days, our step count has failed in different instances.
For my partner, hers failed earlier this year (2021), with just a few steps short of 7,500. In that case, she was so absolutely certain she had achieved 7500 steps on the particular day -- she remembered specifically getting up to do steps in the evening until the watch notified her. Indeed, the VA4s was still counting up her streak record as if it weren't broken, but Connect said her streak had restarted. It's an ongoing case that Garmin support have acknowledged as a potential problem, and the investigation is ongoing. Coming to the forums, I see a few similar cases over the past couple years.
For me, my count failed 14 April with 7428 steps (of 7500 goal) -- ending a nearly 200-day streak. I was also certain that I had obtained my step count for that day, but I couldn't be bothered to argue the case then because it was a fairly inactive day where I would've walked around the block to get my final few steps -- I'm not going to get anyone on my side with that explanation. However, my count failed again on 13 May, with 7473 steps. On this particular day, I made a point to go for 2 runs, in the rain. I am absolutely certain that I had seen the step count go over 7,500 steps, and then several hundred more. I even vividly remember the "step goal achieved" notification near the end of my run. Now I am spurred to act, because I am certain there's a glitch somewhere in the system, and now it is compromising user motivation (which is part of the reason for having these wearables...) on a random and recurring basis.
Troubleshooting
Notably, I noticed that the watch only synced the activities for 13 May, on Saturday or Sunday -- 2 days after the most recent step count problem. This was marked by 2 or 3 Garmin Connect Activity synced notifications on my phone. In fact, I've noticed that Activity synced notifications take much longer to appear on my phone these days, sometimes only showing up hours or days after an activity. I have to wonder if this hints at some part of the problem.
I have a OnePlus 3 phone, with Android 9.