>50% deep sleep reported by SAA, not catching when I wake up to pee

Detailed description of the problem:
Device: Garmin Vivoactive 3 is the tracking device. I use the SAA Android app, with all required add ons.

Issue: Two nights in a row, SAA is reporting greater than 50% deep sleep, which seems impossible. It is also inconsistent with the results reported by Garmin Connect (which also uses my VA3 device for tracking). On the first of these two nights, I was wearing a Fitbit Alta HR, which tracked sleep through the Fitbit app. Both Fitbit and Garmin Connect reported deep sleep values closer to 12-15% deep sleep, which is more in line with expected values, and they match eachother.

In addition, I’ve woken up each of the two nights to go pee, at 5 and 4 am. SAA didn’t catch this, while Fitbit and Garmin Connect did.

Steps to reproduce:
See above. Two nights, cross checked with another device on night one.

Version of Sleep as Android:
On Garmin Vivoactive 3: 20191008
Android app: 20200102