samba - Jun 2005 - Machine accounts becoming "invisble" when using the LDAP-backend

Hello list,

I'm running into a strange problem: about a month ago I migrated my
Samba password backend from tdb to LDAP. The whole process was very
comfortable and everything went smoothly.
But now it happens every now and then that one of the PCs complains
about not being able to find the machine trust account.
A 'pdbedit -L' doesn't show it, either. But when I query the LDAP by
hand, the account is there.
I have found out that renaming the entry (adding a new primary uid) to
some foobar name and then renaming it back to the old uid value makes
the entry available to Samba again.
But this is only a workaround when the problem has already surfaced.
Does anyone know a way to fix this problem?

Greetings
  Marcus