The Better Days mod animates passing of time as you sleep. This features is enabled by default on this mod with the setting "enableSleepFeature = true".

When this is used together with Nomadic Tents, it breaks the sleep cycle and sleep continues throughout the day until the following morning making the player sleep an extra 24 hr in game at least, sometimes several days extra.

With "enableSleepFeature = false" (vanilla sleep behavior) this is not an issue.

Part of this seems like a possible vanilla bug with modded dimensions, I know if I made my own dimension and enabled sleep in it you just lay in the bed forever and time doesn't skip but at the same time you say the bug goes away with the config change so I'm not sure now