Brew head creates a vacuum?
It appears that when I prime my machine
it sometimes creates a vacuum at the brew head. When I remove it to add the coffee
it's held on by suction. This happens maybe
once or twice out of every ten brews.
And while the steamer and wand work great it's been taking longer to brew the coffee.
Do you mean to say the basket is coming out of the portafilter and sticking to the brew head? You can't remove the brew head itself. This could not be caused by suction as the basket is full of holes and there is no suction created at the brew head regardless. More likely it's simply sticking to the brew head gasket; cleaning the gasket with a stiff brush might help. Additionally you don't need to have the portafilter in place to prime the machine, so simply changing that behavior could solve your problem.
If your coffee is taking longer then usual to extract, either your grind has gotten finer, you're tamping harder or some of the holes in your basket are clogged. If you take it out and hold it up to the light it should be clear if that's the problem; a stiff brush and an oil-dissolving cleanser should clean it out nicely.