The problem is in the deck design. The blades throw the grass towards the opposite blade and the impeller has to suck the material up a foot long chute.
There are baffles and guides in the deck which are designed to guide the material but they are not self cleaning.
Wet grass builds up all around the blades and soon it plugs. Going slow of course is essential but I don't see the point in owning a mower you have to clean out every dump if you have shade or dew.
It works fine in dry grass or if you are sucking up dead leaves along the side of the road. Works ok to suck junk out of flowerbeds also.
The second problem is that it is useless in mud or slick grass. The center of gravity is too far back and it puts all the weight on the single caster wheel in the back.
You can't climb hills or mow side hills unless you go in reverse.
And the seat is a brick.
I've found it to be faster to use our Kobota mower to mow everything I can do with a big mower, let it sit a day to dry, and then redo where I need to remove cut grass.
Now I'm going to go swear at it some more.