I just had something like this happen. A lot of my lots were either turned residential when they were previously commercial and some of my residential homes have been turned into community lots. I couldn't move my sims out the traditional way so I went to manage worlds and put them in out of world category and that did the trick. Then I was able to go into some of the lots and change their lot type.
I only noticed this happened when I was creating a club and none of my parks showed up. Then I went into the closest park and it was set to residential...then all my parks. I don't know what caused it and I can tell you that the homes were playing like normal, but I couldn't go into build mode if they were retail or a restaurant.