I don't think your grid lines are the same as those asked about in the original post. Yours in the warning refer to grid line in curtain walls. Curtain grid lines can't be in the same location in a curtain wall because a panel cannot be generated between them. They have to be separate at least enough to allow a panel to be generated between them.
When users want a grid in every other "bay" they need to use the Add/Remove Segments tool (when a grid line is selected) to tell Revit which portion of grids between perpendicular grids should be visible/used or not.
Steve Stafford
Did you find this post helpful? Feel free to Like this post.
Did your question get successfully answered? Then click on the ACCEPT SOLUTION button.