Yeah ....... two thoughts:
First: Always drive around with the top down. It's a Spider, right?
Second: If this is the worst problem you have with your roof, you're lucky. The Spider top is the most complicated device most of us will ever own. Plus nobody really understands how they work, including certified Alfa mechanics. Perhaps the German guy who designed it knows something, but he ain't talking. I suspect if you drove into your Alfa dealership and bet them a thousand bucks (or pounds, euros, or whatever) that they couldn't fix it within 8 hours, you'd wind up with a wad of cash in your pocket 8 hours later and you'd still have a quirky top.
Having said that, I really like my Spider. By the way, day before yesterday I was driving with the top down and got the same warning. I had to cycle it twice to make it go away (for a while anyway).