Loading different .pref file fails to change font

Let’s say I have the following two .pref files, with the following Default Main Editor Attributes:

Blog.pref - single-space Arial 9
Manuscript.pref - double-space Courier New 9

Every time I open a project, I go to my Options and load up the appropriate .pref file so that new documents will be created with those settings.

The bug is this: Sometimes, not every time but reasonably often, switching from one .pref file to the other will correctly change the line spacing but not the font. So if Blog.pref was currently loaded, and I open up my Editor options and load up Manuscript.pref, the preview window will show the example text changing from single to double space, but the text remaining in Arial.

Usually that’s all it is - the font of the previous .pref file persisting despite the newly loaded .pref file having a different font. One memorable time, however, the font not only remained in Arial when it should have changed to Courier New but also changed to all bold.

Everytime this happens, I correct the font in my options and I re-save the .prefs file just in case. I simply don’t know if the .pref file is getting corrupted or if the .pref file is being imperfectly applied.

Further details:

This bug appears to replicate more reliably if I have more than one Scrivener project open at once. Just now had a project using Manuscript.pref open (double-spaced Courier New), then, without closing it, opened one for which Blog.pref (single-spaced Arial) is more appropriate; loading Blog.pref got me single-spaced Courier in bold.