While I am not a front mount mower user, I am a zero turn mower user, and at times this has happened to me.
Perhaps the deck is sitting real front high? If you are bagging like I do, then if the blower is not up to par I get a fair amount of blow out. Also, if conventional mowing, and if the chute gets bunched up grass partialy blocking it, I will get some blow out of the front of the deck, which like you comes right back up on me.
The only cure I have found for the blocking of the chute with the cut grass is smaller cuts, and more ground speed to keep the grass coming out fast and dispersing rather than slow and clumping. I have found high lift blades and keeping the blade tip speeds up (no dogging the mower on hills, heavy grass, wet grass, thick grass, etc) also helps.
Besides that I have been new mower shopping, and I have looked at the F series as well as a new Z series ( I really want a ZD331), and in so looking I see that many manufacturs put a extra front lower lip on there decks to combat the front grass escape.
How about a short rubber lip added to yours?
Or just more ground speed if your back* can handle it to "outrun" the grass clipping?
David
*My back can no longer handle the 15 mph mowing speed of my Hustler Super Z zero turn, I find myself crawling along at regular mower speeds even with a suspension seat.
