duplicated map. Sims too!

I have been dealing with this bug for a long time. As you can see, the map of Britchester is duplicated and has some very visible errors. I can't figure out what it is. Besides that, it happens that the sims get duplicated when we are moving into a house at the end of the terms. And we are stuck in an eternal loading loop but we return again to the accommodation. Could you help me?