JDev 10.1.2.1: Errors after migration from 9.0.5.2

Question

We have a rather large project here.
We're just in the process of migrating to 10.1.2.1 but we're facing a couple of problems. One of them is this:
When JDev loads the business components (for example when we expand a package containing BCs) we get error messages coming from two VOs (each in a different package) stating that entity attributes of the VO cannot be found.
The one VO is pretty much dead, you cannot even open the wizard for it.
In the other VO the attributes are set to transient. I can delete the transient attributes and re-add them from the entity without problem. When I close JDev and reopen it, the attributes are back to transient.
The only thing I can see that both VOs have in common is the entity. The entity is in a third BC package. I cannot find anything wrong with it. When I rewrite the entity nothing (except the version number) is changed. Same applies to the VOs. No changes worth mentioning when I re-create them and compare them to the 9.0.5.2 versions.
Now the strange thing is this:
As I wrote before, the errors come from two VOs in two different packages. The
entity is in a third package.
Now I have just observed:
I close JDev with the package tree in the Applications Navigator closed and
restart it.
I then navigate to some random package and open the bc folder -> one error from
both VOs.
But when the first bc package is one of the packages with the problem VOs, then
only one error is produced: from the VO in the other package.
Example: I open a fourth BC package accounting.bc first -> two errors
from multiplepatientid.bc.MpiAuthorityDomainLovView and
staff.bc.StaffMemberAliasEditView.
When the first BC package I open is staff.bc then I only get the error from
multiplepatientid.bc.MpiAuthorityDomainLovView. StaffMemberAliasEditView
works!
When the first BC package I open is multiplepatientid.bc then I only get the
error from staff.bc.StaffMemberAliasEditView. MpiAuthorityDomainLovView works!
Weird isn't it. It seems to depend on the order in which Jdeveloper loads the
BCs.
I tried to re-create the project file, to re-migrate the workspace .... nothing has helped.
The application still works as expected. Just JDev fails to load the business components.
So, has anyone encountered a similar problem so far?
I created a TAR for that but the support guy is as puzzled as I am.
Sascha

Answer 1

Just for the record:
This is bug 4669535. We received a one-off patch for it.
Thanks to everyone at Oracle who was involved.
Sascha