After the Captain and first officer were killed, Lt. Commander Picard took command of the Stargazer. But did he keep command? Or subsequent was a Captain of rank placed in the Captain's chair and Picard taking command (his first command) of the Stargazer only sometime prior to Jack Crusher death?
Picard, after briefly being in command of the Stargazer, might have serve on different ships, in different capacities, reaching the position of first officer on one of those ships. And only then returning to the Stargazer as it's Captain.