Managers don't get the luxury of "off the cuff" comments. This is because the people who work for managers pay attention to know which way to go. The higher up in the organization, the bigger the risk.
This applies to front line managers as well as company and political leaders. In the eyes of the team, things you say carry extra weight. Which means that you may say something that you think is just "verbally thinking through options", but the team sees as a firm direction.
What ends up happening is that the manager forgets the casual comment right after it is said, but the team sees it as a direction and starts to do work. Then the manager needs to stop and re-direct the team latter. This leads to confusion, frustration, and a loss of trust. The team starts to wonder which of the things the manager says is just a thought and which is an actual direction.
This doesn't mean the manager can't have casual comments, but he has to be clear he communicates that. Say something like "I'm just spitballing here, no need to take action on anything". Just let the employee know that this isn't direction.