Volvo D13 2013 i shift rough start

Hey, We have 2013 D13 with ishift gearbox and having issues with clutch.
When stoping and starting 8 times out of 10 there is a issue with starting driving again. Put it in Drive, selects a gear, accelerating and it feels like the clutch is not engaging smootly. Its like the clutch hesitates to connect with flywheel or not,clutch 10%-30%-10%-30%-and suddenly 100%. The problem is there only when starting from standstill, while driving its all smooth.
Gearbox had been rebuilt by volvo 13 months ago (warranty ended last month), few days ago we replaced clutch control unit on the side of the gearbox, got it calibrated and now there is a fault on the dash, check transmission next stop, it wasnt there before the new clutch control unit. But clutch hesitation problem is still there.
Any ideas, what to check or do before taking the gearbox off?

 

Changed the brake switch with the big air valve (5 hose connections) behind the brake pedal, no change.
When i push the accelerator like 5%-20% the engine rpm rise about 50rpm, engine acts like i am moving the accelerator up and down 50rpm, give more gas and then suddenly the truck jumps and goes

 

The clutch main bearing was broken.