I have an installation with several plone sites, a base theme (with skinlayer and z3c.jbot overrides) and specific themes for each theme that redefine only css colors and a browserlayer.
I noticed that (randomly) in some instances z3cjbot's overrides aren't loaded and i see the default ones (for example the header and footer viewlets).
I say "randomly" because some sites in some instances has problems and other not. And restarting them several times, this situation changes in a non predictable (for me) way.
In the same buildout there aren't two products that overrides the same viewlet (for example the header).
What's the logic behind jbot? Why sometimes overrides are not loaded? Some strange order behavior?