It's great to see that GpgOL 2.4.4 can correctly handle an obscured subject line when rendering an encrypted message.
However, it looks like it is explicitly displaying the legacy-display part for some messages that it doesn't need to display. see the protected headers spec for a specific algorithm for detecting a legacy display part.
I'm attaching screenshots from the protected headers test corpus that demonstrate the issue. You can see the problem if the first line of the body appears to be "Subject: BarCorp contract signed, let's go!"
Unnecessary rendering of legacy display for pgpmime-sign+enc+legacy-disp.eml:
and for pgpmime-layered+legacy-disp.eml:
note that it *does* sometimes hide the legacy display part, for some messages, including unfortunately-complex -- that's good! -- but maybe this points to some internal inconsistency: