So because your master is 20 steps your kick will have to fill in the blanks with those 4 spare steps as it is only 16. If you make your kick 32 steps, and master 32 steps you will get the effect you desire (but you’ll have to fill in the extra kicks in your pattern).
The hat still being 20/32 will loop once it finishes it’s 20 steps and you will get an interesting poly-rhythm.

Whatever pattern length is shorter than the master will loop once it’s length is reached. At the moment your kick is the shorter pattern, so the “void” occurs, where the 4 extra steps are played and it goes out of sync. The hat is staying in sync because it’s matching the master length.

So to re-iterate.
Set kick and master to 32 steps. Fill in steps you want.
Set hat to 20.

Voila!

EDIT: I’m stupid. You could also just change the master length to 32 and not change the length of your kick to 32 at all. Problem totally solved!