I see a few common problems with comedy specs, but none so much as trying to be funny without laying the foundation.
Comedy plots should be built like cakes.
First you figure out measure out flour (what the character wants).
Then add eggs (antagonist).
Add baking soda (conflict).
Pinch of salt (flaw being exposed).
Stir things up. Then bake.
When the plot has cooled, then ice with the comedy layer.
Why is comedy last? Isn't the audience looking for the funny?
Yes, the audience is looking for that icing layer. They want to laugh.
But as soon as they take that first bite, they will spew it out --- unless there's a good foundational cake underneath.
WHAT I'VE LEARNED: Although cakes are consumed icing first, they are built cake first.
I can spot new writers b/c their comedy scripts have no plot, & are based on joke-joke-joke.
Real writers set up the script as if it's a drama. Then upon rewrite after rewrite, they add the comedy, jokes, prat falls, etc.