Rename title of baseline removes policy

[ewohnlich]

Plone 5.0.5
plone.app.iterate 3.2.0

Steps to reproduce
Create a page. Checkout page. On the baseline, use the Rename action to change the title (not the id).

Expected Behavior
Baseline title change (or maybe fails, because this should be locked?), policy zc.relation remains

Observed Behavior
Baseline title change, but policy zc.relation is removed. This appears to occur when the event listener is notified in the plone.app.content.actions.RenameForm view.

(Pdb) ICheckinCheckoutPolicy(self.context).getBaseline()
<Document at /ootb/front-page>
(Pdb) notify(ObjectModifiedEvent(self.context))
(Pdb) ICheckinCheckoutPolicy(self.context).getBaseline()
(Pdb)