Yeah, city updates can cause fluctuations in counts and stats.
You can enable notifications when a city is changed in your settings page. That might help give a better view on the underlying changes, but it may also get a little noisy.
Also, my overall city maintenance (adding new cities/countries, merging cities, etc) can do the same. For example, I just merged a bunch of Flemish towns today. If you didn’t run in those cities, then your counts wouldn’t be affected … but rank could still be affected, if you’re watching your global rank that closely. 
Edit: 
I’m sorry, I was in zombie-support-mode and just focused on the technical issue … I hope you’re able to stay safe & the worst of this fire for you is some time away from running 