Content-objects broken

With ZMS 2.11.1-51 the import of Content-objects (*.metaobj.xml via file
upload) is broken:

It seems to me that the setup of the structure while importing is buggy.
Using such an object results in faulty user interfaces (wrong input types)
and faulty object infos (createdatetime, multiling). 

The re-saving of each single Content-object in Configuration-menu helped
until now as a workaround (first I thought the reason are versions of older
objects with v0.0.0 - but the problem persists with correct versions like
v1.0.1).

It was also seen that an active (!) Content-object is not been listed in
"Add to Folder/Document"-dropdown - maybe this is the same context...

--cm