Just recently purchased a 2020 z800 ex and when I go through creek crossing around floor board deep maybe a little deeper the machine will start to hesitate and stutter for a few mins then it clears up I've put dielectric grease in every every connector I can see and on spark plug boots checked air box and belt it's dry I'm stumped

Floorboard deep should be fine as I've had water over the sides and it keeps going.

Did you check the air box to make sure it is sealed? Perhaps water is getting into the filter area and the engine is getting an unwanted drink.

Does the ECU light on the dash illuminate?

No light flash and air box is dry and sealed sputters for a few mins then it's fine I'm lost

[2015 Z Force 800 53/Trail EPS]

I think I answered this on FB but did you check for moisture inside the main fuse holder? Floor level...that's about the only thing electrically but some splash could get up to the front cylinder's plug..might check if it's on well.

Yes I checked there and added dielectric grease
And still have the same issue

Hmmm .... Tough to narrow down.

You could try using a water hose to spray various components/connections/wires/etc.  to see if the sputtering returns.