For now it looks like we've managed to "solve" the error by creating 1 new object of this entity, after this the page is properly displayed with an empty column where there is no association without the error.
We fixed it by adding a new object of the entity that caused the problem. It seems like the association did not exist anymore and by adding 1 new object the association was there again. Older objects that do not have the Creator stored are displayed properly again w/o data.
"failed: path 'System.owner' does not refer to a valid association" this is the error, in my entity, I selected the system member, has some relation with that