I would say that some daylilies do change foliage habits because they acclimate to their environment. However, after that many years in one location I would have to say it wouldn't because of the environment. IMHO if they normally get no attention and then all of a sudden got "fed" that would probably be why your dormant stayed green; it may not actually be a dormant but went dormant trying to conserve energy since it was neglected.
In my area the dormants don't usually go dormant, they act more like semi-evergreen even with the cold and freezes we had all winter.
