Well, they should be the same, so that is a concern. And yes, a sticking slide could give you the same symptoms.
When dismantling/handling those diaphragms/slides you need to be very careful with them. That rubber is very thin and carb cleaner can weaken and/or bubble the rubber and can result in a tear.
A torn diaphragm needs to be replaced.
Both springs need to be the same when removed and set beside each other. If they are mismatched, a previous owner has botched the job.
The metal slide, jet needle and the carb body can be cleaned with carb clean to make sure there is no gunk or varnish, just be very careful not to get any on the diaphragms.
Carbs need to be extremely clean to work properly. Not just free of obvious gunk, but thoroughly clean of any lingering deposits.
Best of luck!