We was not able to reproduce the issue. Are you using the web interface or the API in order to perform the SIS import? How big is yout csv file? Could you attach (or send by mail if it contains sensible information silvio @ bitnami.com) your csv file?
Regarding your other question, Bitnami canvaslms stack does not use the canvas_init script. Instead, your can perforn
/opt/bitnami/ctlscript.sh restart canvas_init