>> What version of ZODB are you using? > > Whatever ships with Zope 2.9.8 I think that is ZODB 3.6 which is on the older side. I was simply noting that there are several invalidation fixes in ZODB 3.8; whether they fix your problem I do not know. >> If you have zeo on in debugging > > What does this mean? Turn up logging in zeo.conf to DEBUG