Hi @TrulsB,
Welcome to the forum!
How to resolve this will all depent on your model, so…
It’s important to provide as much context to a question as possible. This includes the data, the model, the formula, the filter context etc. And know that this forum is public. So if your data is considered sensitive - be sure to post a muck-up.
Since you have two dates to take into account, I can already suggest looking into this technique.