I would definitely cut way back on watering, as you have done. The IFAS PDF you posted indicated that 3-4 weeks after seeding the lawn should be established and you should only need to water on an as-needed basis. They provide this link on watering:
http://edis.ifas.ufl.edu/lh025
I didn't read the whole PDF so maybe this is different for Bermuda, but I have always avoided fertilizing an area that has a fungus or other disease until that issue is solved. I would get a bag of fungus or disease control made for Bermuda and apply it to the area and limit watering to see if it responds. If it doesn't respond to the treatment and reduced watering in a couple of weeks (or gets worse) then more research is needed to figure out exactly what it is and how to combat it.