Strange Problems with User-Logon after Migration to Plone 5.0.5

After we migrated our Site from Plone 3 to Plone 4.3.10 and then to Plone 5.0.5 we encoutered a strange Problem with ActiveDirectory User-Logons.
In our Tests we had no Problems, but after going live and the Users tried to Login the Problem was the following:

Some Users logged in without Problems, and some were already logged in, when opening the main URL - with another User-Account.
Did someone else have this Problem before?
I think it has someting to do with plone.app.ldap and the caching enabled.

Our buildout.cfg:

eggs =
Plone
Pillow
plone.app.contenttypes
lxml
Products.CMFDefault
Products.LDAPMultiPlugins
Products.PloneLDAP
dataflake.fakeldap
five.formlib
plone.app.form
python-ldap
plone.app.ldap
wicked
plone.app.multilingual

At the moment we switched back to our old Plone-Instance.
I hope, we can find a fix for this within the next days.

Any help or suggestions would be nice.

regards,

Jan

This sounds like a http caching issue. You can test whether that's the case by disabling caching in the plone.app.caching control panel, and also disable any accelerator you've got in front of Plone (like Varnish).

The split view caching policy that ships with plone.app.caching is not solid IMO. I've had to tweak that extensively, exactly to avoid the scenarios you're describing, in an installation without LDAP.

Thank you for your quick reply.
I have disabled caching now, and will test with a couple of users tomorrow.