My ds does this all the time with out provocation from either parent. I'm sure in some way he thinks it will gain him the approval of the parent he is with at the time.
I talked to my x about it when I first noticed the behavior and suggested whenever either of us or ds' step mom hears anything similar we all simply reassure ds that we all love him very much and all want to spend time with him, but scheduling days and times is grown up stuff, so he doesnt have to worry about it.
