I was able to select the
2-Park Universal Express Unlimited Pass
Universal Studios Florida + Universal's Islands of Adventure for May 21st with no issues. I didn't buy it so I can't speak to the full purchasing process but I was able to select multiple days in May.
And doing it as a
2-PARK - 3-DAY Park-to-Park TICKET + 2-PARK UNIVERSAL EXPRESS UNLIMITED™
Universal Studios Florida + Universal's Islands of Adventure
Start Date: May 10, 2020 works for me even though no dates are shown as available. It still lets me select them.
Again, I didn't go through with the whole purchasing process but I'm guessing its a glitch in the system. Not sure what would be going on the entire month of May to prevent it especially when its available when I tried it from the 1st method I mentioned.
Is that what you were talking about?