I still am convinced that it's a perennial type of morning glories. Moonflowers tend to come open at night. If you painted them blue, I took a cutting of my neighbors vine and rooted it and put it in my old house garden. It totally took over!! Luckily I liked it and so did the pollinators and hummingbirds. It would even crawl across the cement driveway and up my house, everywhere. It was pretty easy to pull the vines up and cut them back but it would just do it again. I never had that problem with the seed morning glories.
Obviously I Love morning glories lol.