Observed by me and everybody I know who had this issue, consistently, same hours, same periods of time. Sometimes it was all of the people playing the game in one group, sometimes just one of them. Those people are from different countries, though some live in the same country, and my pal lives in the same city as me. Regardless of georaphical location, it was always the same hours - evening hours (our, EU, tz) when we played. All of those people have experienced severe desync issues in the 2-3 weeks following HS release, again same evening hours - and getting 2 times worse during the free play weekend which brought in even more users.
This isn’t a pattern that supports all those theories of “bad internet connection”, in contrary it clearly points towards FS’s infrastructure not being able to handle peak loads. There is a thread on the issue starting more than a half a year ago with dozens of people reporting desync issues and posting logs, those posts were still coming in a month ago (last time I checked it): INVESTIGATION: Disconnects (Error Code: 2001, 2014, 3013, 4001) & General Connectivity Issues
The fact that you didn’t experience it means nothing, it’s a big, global infrastructure with multiple ingress points, load balancers, regional servers and such. It wasn’t always consistent even within single region (often only one player on the group had the issue - but then next day he played ok, but somebody else from the same group had it, sometimes they lived in different countries even). What always stayed consistent - it happened during peak online hours.