Need a new Level in your project? Don't just copy a view and rename it! All you get is a view with a "nice" name but it isn't related to the Level you think it is.
A new Level must be created with the Drafting menu > Level tool or via the Basics Design Bar Tab > Level (okay its in a couple more places too). You can also copy a Level but no new views are created when you do that. Which is probably how people end up copying views to make a new view for their Level in the first place.
This dialog shows the Associated Level parameter. Note that it is read only (gray and not editable). This view is forever associated with Level 1. A nice name like 15th Floor does nothing to change that.
Need a new View? View Menu > New > Floor Plan or Ceiling Plan or Basics Design Bar Tab > Floor Plan or Ceiling Plan.