Since Alda is absent for most of the 'Temporary Duty' episode, I wonder if that was his way of making up for the 'Hawkeye' episode which was just him.
Careful, Roy That coil might break.
Oh. I'm sorry, BG
"J"
Let me fix it for ya, JG
It's possible that he was finishing off movies that he was in during that time. On the show Murder She Wrote, Angela Landsbury had a few episodes in a row where she only narrated them at the start and/or end.
The same thing could've happened with that episode. Alda could've been finishing off one of the two movies released in 1978
Same Time, Next Year, and California Suite.
His two short bits, at the start and the hug from Charles at the end, could've been recorded weeks in advance. Like Angela could've done for MSW. Record those parts at once, and then cut them into the episodes later.
Destroying an empire to win a war is no victory and ending a battle to save an empire is no defeat