Source Track Produces No Sound When Track Duplicated

When I duplicate a track (either with pattern data or without), the source of track I duplicated from no longer produces sound. The note data is still there, the track is not muted, it just produces no output (nor registers output on the track scopes)

Anything I’ve missed?

If you are using external instruments, such as VSTs, many of them only have a single output so can not create sound on more than one track at once. Use Instrument Aliases.

If using internal samples then I have no idea.

Ah, I suspect Option 1 applies here, thanks.