When my sims try to talk With eachother they talk then suddenly they Are reset. So its not possible to improve relationships because they Are reset before they can do anything. This only applies when 2 or more sims ineract. They can do stuff alone without getting reset.
@Damafter are you using any mods or CC?
here do this, since this is likely a mod issue, install a mod called Better exceptions when loading your household using this will scan your files and then create a list of all the possible mods then it will be process of elimination. Other than this you can also run BE and do an interaction it will then show an exception report of the mod or files that caused the issue.
This is happening to me on console right now. Started with the high school patch.
