Comment 11 for bug 1598938

bibisecting suggests

commit 135e4d5c730b8b252eab3e375580a3a73d8204e6
Author: Michael Stahl <email address hidden>
Date: Thu Apr 23 22:52:39 2015 +0200

    related: tdf#90820 refactor SwFrm destruction

is the trigger, though I rather feel that's not at fault and we just got away with things earlier