Very many technical raincoats, if not all, will have laminated zippers and taped seams, which makes the jacket waterproof and helps you stay dry.
Almost all raincoats, in general, will have taped seams, but not all will have laminated zippers – instead, they will use storm flaps if they lack the feature.
Note that a laminated zipper will make the jacket more difficult to zip down and up, so thrashing it will worsen things and even break the zip itself.
Be patient with them as much as you can. They will also have a covering (zipper garage) at their tops when you do the zip-up, and this protects the zipper from environmental exposure.