Source: Statmuse query
Coincidentally, his opposing QB today, Joshua Dobbs, is #4 on the list with 0.90 fumbles per game (18 fumbles in 20 games including today.)
Ryan Leaf is between those two QBs with 0.96 fumbles per game with 24 in 25 games.
I’m surprised to learn they’re not. I think a fumble is generally credited to the last player that controlled the ball. So a qb will always be credited for a bad qb-rb exchange, for example, even if it’s the rb’s fault.