When I open my tree, the tree of the last person I was viewing opens, not mine. This happens on my personal PC, and at the FHC.
For me, the tree/person displays as expected in Chrome but not in Firefox.
There have been other reports of problems in Firefox in the recent past.
Firefox at home, Chrome at the FHC. My own tree not opening with both Web Browsers.
I've noticed the same thing. When your tree is displayed, hit the icon of a home in the upper right hand corner. This resets the home person to you!
Have you tried resetting your FamilySearch cookies?
Both the "Home Icon" and "Reset FS Cookies" suggestions did not help.
@DavidNCraig Let me suggest you schedule an appointment to meet with support to get help with this issue. Go here to the Contact Us page, then scroll down a bit and select schedule an appointment.