The OpenSCAD releases seem to be in chaos. I've been using an AppImage release in Ubuntu, build 9.4, since February. Later releases seem to just crash. I get the feeling I'm building on an unstable foundation. :-(
Perhaps I'll just use AppImages like you so that I can finally upgrade off 16.04. Have you found any downsides to using the AppImaged version over the apt one? (aside from the stability issues in newer releases)