famoma2018 Endless loading screens means that the game ran into something wrong when trying to load the lot you travel to and can't find what went missing and keeps on trying. So, the only way out as you probably know is to force quit. It can be a sign of file corruption but usually, it tends to be a broken CC/mods or if the lot was downloaded, a glitched lot which there are many in the Gallery. There is a current issue that several zones become inaccessible throwing you into an endless loading screen in a save where the lots either appear to revert to what they look like in a new game when you look at them while on a lot in live mode or are invisible depending on which world you're in. If you don't have the reverting lots issue then, it's most likely to be one of the issues I mentioned earlier.
Neighboring Houses show as Default/Empty | EA Forums - 11903590
I'm not sure what events you mention are, but I am assuming you're talking about the City Living festivals, Cottage Living Finchwick fairs, and Island Living turtle event that you get a popup for or when traveling to a party location which you get via a phone call. So, more information on specifically which events are involved when you run into the endless loading screens would be helpful. And it would also be helpful to know what platform you play on and if you use mods or not as well as if you can possibly identify which lots you travel to where you get the problem.
Hope this helps.
