I believe we have an error between teams and planner.
We have created a two planners in Microsoft teams
When we click the pop out window it opens in tasks.microsoft and the tasks are assigned to the correct people and the tasks show.
Clicking on the planner name on the left however connets to the other plan from within teams. The tasks from the original plan are unable to be found in planner, but remain available through the My Tasks icon. The other plan from teams shows.