UPDATED UPDATE: This is happening in front end editing even on regular items, now, too. Padding and margin settings on various addons and rows work fine, until I click the close button in the bottom left. It appears that there is a temporary file while working in the front end that does not get written out to a production file. I've just run Akeeba Fix Perissions (again) but....
The reason I am doing this is the client attempted this and had the exact same problem, so now I'm working for free.
Superadmin credentials in the hidden field, above.
UPDATED UPDATE TO THIS UPDATE: Might this condition be the cause this: when I enter via the 'Edit Page' directly on the front end, rather than launching the Front End Editor from SPPB? ie, a session ID must be issued from SPPB for this to work properly?