I do not know anything about IMGBurn, but the Shotcut export default is MP4 (not changing anything, not choosing a preset, clicking Reset within Export, or choosing the preset named Default). I highly doubt you got AVCHD, as that is MPEG-2 Transport Stream, and you have to go out of your way in Shotcut to create that. The things you are asking about are in a section of Export labeled Advanced. I do not recommend you change anything in there unless you are advanced.
Maybe you need a properly encoded file suitable for Blu-ray to work with this program.
In that case, we do not have a Blu-ray preset. It might be possible to still output, but I do not know enough off-hand without doing a lot research.