I posted this over in the PC/Mac - Bugs & Gameplay issues and was told to also post here.
After the latest patch and installing Seasons, I am experiencing a ton of lag on community sites, like coffee shops, spas, restaurants, any of the festivals, etc. It doesn't seem to matter what "city" I'm in - San Myshuno, Windenburg, Newcrest, etc. I'm not sure if it's the number of Sims that are on the lot, perhaps? Maybe it's somehow increased after the patch or new expansion? I never had a problem previously, but my Sim is becoming a hermit because the game is unplayable on community lots.
For what it's worth, I'm playing on a Mac with OS High Sierra. No mods or CC. I started a brand new game after the patch and installation of Seasons with just one Sim in my household. I have gone through all of the standard Mac user things to try - repairing the game, dumping some of the cache files, adjusting graphics settings. Nothing has seemed to help.
For now, I'm blaming the new patch and/or Seasons, as I never experienced this before.