To sum up the other comments:
Don’t worry it’s nothing.
PS: if you don’t have a professional do something about it quickly your house will explode.
That’s why I stopped asking / reading answers about this kind of stuff on forums, and have a professional come and see to give me a real advice. Every case is different and reading random advices on the internet can bring a lot of anxiety. Especially if you decide to do nothing while some people told you that it could be really bad.
Just made the transition, couldn’t be easier. Export, import, profit