Neither, because I am not using that unbearable email client (looks & feels like, and probably is, Nokia's Modest, which has been Maemo5's weakest point a decade ago!).
But I can confirm that the volume bar does not show up, when pressing the "volume up" or "volume down" button, while Devicelock faith text is active (as strange as it sounds, technically), 100% reproducibly (on an Xperia X) and solely by it (e.g., with no other Patch applied). Setting the volume works fine, one just cannot see the volume level.

Although there is another (single) confirmation for both bugs at TJC (IIRC also on an XA2, like the original report by @peterleinchen), please keep Devicelock faith text available (even with those bugs), as retracting it will immediately reduce the number of testers and people having the idea to analyse and fix these issues to zero.