Sounds like another case of people being the problem
Sorry, couldn't resist. I'm kind of joking, but mostly not. These types of inconsistent signals can definitely confuse a dog. Try to convince them to see things from the dog's perspective. If someone tells you not to do something, then a few minutes later asks you to do the thing they just told you not to do, wouldn't they be confused as well?
Consistency is KEY in training. The same behavior should result in the same result EVERY TIME. It's not a case of rewarding when it's convenient for him/her. Rules exist for a reason and most dogs thrive on them. If need be, set the rules with your family and enforce them no matter what EVERY TIME. If the humans aren't consistent, how can anyone expect the dogs to be?
Hope that helps a bit.