Get some glass that sheets and put any sort of polish on it and it will bead- forever, because the coating sinks into the pitts of the glass and causes adesion to any thing on the glass like water. You usually get it on the downstairs in paticular when the customer has been polishing their windows but you also get it when the bl***y installers clean the glass with silicon based petrolum products.
I have just had a bad hair day as well . The sun is at a low angle the sky is ultra blue and spots show. I had one job that is hydrophillic -water loving ie it beads, I went back and did them again after the first clean had dried. I dont usually have to do this but did today and I will have to watch things tomorrow as well.
You hopefully wont always have these problems you just ned more experience I notice you had your system in January and things seemed to be going OK maybe you are just putting yourself under the microscope and finding fault with your own work ? which we all do.
Persevere ?