Urgent help needed: Fills and objects went weird

[Stefan Videnov]

Hi everyone,
As the new year looms so do deadlines and I may have overdun the merry cleanup this time.
I saw that  hundreds of fills have snuck up in our BIMcloud project and a lot of objects don't display properly. For example in the object bellow there shouldn't be any hatch: 

When I deleted the extra fills shown abovea lot of objects from the dutch KeyMember library got shown only in black.. 

If I try to reimport the old fills from a backup they do get new FILL IDs so that didn't work, even if I say "override".

I Opened the object (ctrl+shift+O) and I saw that the object is using fill id 64. I then set 64 to be Dicht Arcering (or the dutch version of Background fill) as it is in the template , but the object still stays black.

I have of course checked the objects settings and the graphic overrides, but the cause is something else.

Here you can see that in the project and in the template the object uses the same fill with ID 64

Any ideas?
Thank you!