The call fetching the targets mistakenly used the timestamp meant
to back up the TIMESTAMP atom (hence, it's the timestamp at which
the selection is *owned* by the compositor, on behalf of a wayland
client).
This timestamp is actually only updated when the compositor gets
to own the selection, so it's a randomly late timestamp to retrieve
the TARGETS atom content, which certain clients might end up
ignoring.
https://bugzilla.gnome.org/show_bug.cgi?id=768007
21fd87c4af