BUG: Bass clef for tenor voice rendered an octave too high

I came across something very strange when importing MusicXML from another product. I cannot get the Singers > Tenor player to render correctly in a bass clef. It renders the line an octave too high. During playback the notes are played in the correct octave, and if I change the clef for that staff to treble-8vb it renders in the correct octave. Attaching a couple of screenshots that illustrate this issue. The only difference between the two screenshots is the clef has been changed.

Can someone explain why this is happening? Seems like a bug.

Octave clefs do not transpose under the hood, so HALion is set to transpose the tenor voice patch by an octave. This certainly isn’t a bug - it’s working exactly as designed - but search the forum and you’ll see it’s been discussed at length.

If you use the HALion player, you can adjust the transposition there, and there is also an Expression Map setting, but that makes switching back and forth from an independent Tenor staff to one combined with Bass nearly impossible.

IIRC there is talk of an option to allow the tenor clef to shift.