My son did this whenever I worked nights or had night classes. Nothing ever changed it, until my schedule changed. Even though he was with my parents and his dad, apparently he just needed mommy time, and figured out a way to do it. When my schedule would go back to more daytime hours his sleep pattern changed...usually after about a week.
We never had any luck TRYING to get it to change any other way. Note that we tried. It wasn't until my schedule had changed a couple times that we noticed the pattern. But it never failed. An hour or two home, ready to sleep & he would wake up. Sigh. What you do for love.