Yep. He was just an observer when they got thrown into the Delta Quadrant. Janeway gives him Lieutenant Junior-Grade and then bumps him down to Ensign before bumping him back up to LT-JG. Tuvok gets promoted from Lieutenant to Lieutenant Commander at the start of Season 4.
Wasn’t Tom Paris promoted, demoted, and promoted again in the run of the show?
Yep. He was just an observer when they got thrown into the Delta Quadrant. Janeway gives him Lieutenant Junior-Grade and then bumps him down to Ensign before bumping him back up to LT-JG. Tuvok gets promoted from Lieutenant to Lieutenant Commander at the start of Season 4.