Yes, same
Was starting to think it was my custom scenario map that was the problem…
I’ve reported this several times since the May 16 2024 “stability improvement” patch
Here is a post I made with several examples of the lag, which like you mentioned, usually starts around the 1 hour mark: In-Game Freezes for up to 5 minutes at a time!
Here is another post about memory leak issues currently, which may be causing the problem: Computer Memory Usage Increasing while Playing
I eventually made a faster version of my scenario that ends before 1 hour until this gets fixed, maybe you can make a fast diplomacy map in the meantime while it gets fixed?