2006-2023, 109 QBs have had a fumble rate of 1.5 per game or higher. Of those 109 QBs, 1 has played in more than 6 games. (Nearly all of them played in only 1 or 2 games.) That man was Arion Worthman, who played for AFA, played in 10 games and averaged 1.5 fumbles per game. That's Jake's company of other players in the last 18 seasons who have averaged 1.5 fumbles or more per game for 6 or more games.
I'll readily admit my stat source does not easily allow me to cross seasons. Retzlaff's 6 games crosses seasons, so if there's another player with a stretch like this, I can't see it.