If you edit the radius or brightness of any of the Christmas Light string items, those edits to their settings reset upon reloading the condo, making them full brightness and 500 radius.
I really hope all of those items get a rework this holiday season, honestly. Their placement is janky, they can only be placed in a straight line without any custom length settings, their colours can’t be manually set, and regardless of how long the string is, they only have 2 light sources, on the first part of the string.
(Edit: I didn’t include a version originally because this bug has been apparent for a long time now and wasn’t related to any specific update)