I see this as well with HTML emails but not plain text ones. Possibly related to or caused by the issue in this upstream GTK+ bug report.
https://bugzilla.gnome.org/show_bug.cgi?id=699574 -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org
