I've noticed that if you switch to double-page mode while also using manual zoom the image zooms to 150%, rather than maintaining the zoom state you're already in. This problem DOES NOT arise, however, when using other zoom modes, like fit width, fit height, and best fit,
When this happens I manually zoom back out to 100%, but if I later switch back to single-page view the zoom decreases to 66%.
This happens regardless of whether manga-mode is on or off.
Comix 188.8.131.52 (from getdeb.net), Ubuntu 8.10