Note won't play on final volta

I created a score with a repeat and an alternate ending using voltas. It plays as desired. (I had to figure out to edit the final measure before the repeat symbol to tell it to repeat three times, though. That was not exactly intuitive.)

Then I copied the score that works to a new name and added another instrument (voice). I added lyrics for the new voice and I made various changes to the score formatting, chord-name rows, etc. The new score won't play the chord comprising the ending under the final volta.

I tried copying the bar that works from the first score and pasting it into the new score where it won't play. I also tried deleting the measure/chord that won't play and recreating it from scratch. But it still won't play.

Is this a known bug, or do I have to upload the MSCZ file?

/dman