Higher game speed (3x) on advanced cities won't work anymore

[hievor]

When the game is advanced pretty far (like >100k pop) and there a lot of things to sync, if time is seperating heavily, like positive 10 days difference from client to host, the game stops from time to time completly on clients for several seconds until the server has catched up.
Client cannot build or do anything at all in this interval, which is the annoying part.
2x speed is still working normally ,atleast it's not recognizable yet, but I guess with more to sync this can become als problematic as time differs there also by around +1/16 of a day per day tick from server to client.
On 3x we get already around 1/8 of a day in which the client is in front of the server, the stops come when the client is ~1 complete day in front of the server)

Log files show:
[20:19:29.7726] [Debug] 9 dropped frames!
....
[20:19:30.9930] [Debug] Received SlowdownCommand
[20:19:30.9930] [Debug] Dropping 208 frames in the next

Cities Steam Version, all dlcs deactivated, no mods.
Seperate client for server, game is hosted through port forwarding method