If you enter your house (or perhaps other buildings as well), while having Royal Guard followers, they will become stuck inside the building once their Defense Contracts run out. They will then attempt to return to their guard towers by repeatedly running into the corner (see screenshot).
You can remove them by killing them or giving them another contract and leaving the house, causing them spawn with you outside.
Steps to Reproduce
Hire a Royal Guard with a Defense Contract Go inside your house Wait approximately 2.5 days for the contract to expire
This issue has not been confirmed by a developer yet.