I'm having this exact same issue.

White pasty cement consistency that builds up on the dishwasher drain spout.

I actually had to pick away at it with a screwdriver and it broke one of my smaller screwdrivers.

I just did a new renovation and after a week the stuff built up to the point that it clogged and my dishwasher pump couldn't push out the water.

I thought maybe it was the powder dishwasher detergent

Any help is much appreciated