I have two installations of Logos with the Startup option Most Recent - Local and hadn't started the Desktop in some time. Well, the layout content was an 'unexpected' single panel even though it carried the correct layout name. I noticed there are exactly 10 Application Closed layouts but none of them is 'local' as I had been doing a flurry of startup tests on the Laptop!
Whilst "named layouts" are "automatically deleted on startup if they are older than 30 days, or if there are more than 10 backup copies" it appears that it also applies to Application Closed backups.
(I was able to recover the basic layout from the single backup on July 14).
(Please visit the site to view this media)
EDIT: after a restart Desktop still has 10 Application Closed, but there is one recent 'local' backup!