Displays store information about old panels

So I noticed this when working on a module for my site to greatly simplify the creation of custom panels. As is stated in the KNOWN_ISSUES.txt, WYSIWYG editors won't work on the Panel content page. Since most of my users are complete novices, I'm working on a module (which I call 'simple_panes') which simplifies this process, and ends up mostly removing all the fancy JS as a result. Anyway...

My module directly relies on adding panes with a one form to one pane structure. So I need to do direct database manipulation to add my panes. It all works fine except for one small bug I think I found.

On one of my displays I originally created it as three_col, and added content, then changed my mind and changed the layout to onecol. In the layout field in the panels_display table, it has the correct 'onecol' information. However here is my panel_settings field information:

a:6:{s:5:"style";s:15:"rounded_corners";s:14:"style_settings";a:0:{}s:10:"edit_style";s:19:"Edit style settings";s:10:"individual";i:0;s:5:"panel";a:3:{s:4:"left";a:2:{s:5:"style";s:0:"";s:10:"edit_style";s:19:"Edit style settings";}s:6:"middle";a:2:{s:5:"style";s:0:"";s:10:"edit_style";s:19:"Edit style settings";}s:5:"right";a:2:{s:5:"style";s:0:"";s:10:"edit_style";s:19:"Edit style settings";}}s:3:"did";s:2:"34";}

This isn't very readable, but note the inclusion of 3 different panel styles. Left, middle, and right settings are still present. Since this is loaded into the display object, it makes $display->panels contain not very useful information (I'd like it to contain just the current panels instead of the old ones). This means that for my module, as a work around, I'm going to have to use the layout information to regrow the panels part of the display object.

Am I doing something wrong, or is this actually a bug?