As the user of many Cubase versions since VST 3.7 (now using 7.5), one thing that has been certain: when you get to a point where bouncing tracks is necessary, you shouldn’t lose anything at all within your project. HOWEVER (you may have expected this …):
Before you bounce, be sure that all of your track levels are where you want them to be. If not, you may have to go backwards to fix the problem level (which is possible PROVIDED that you save your new bounced track mix as a new file). Back when my computer had limited capabilities, this process was simply annoying - but at least it didn’t require me to re-record a whole batch of tracks from scratch.
On a sidenote, thank God for automated mixing!
This applies only while you’re working within Cubase. Another poster has already told you about this. Sending your file out to an external processor and back into Cubase? All bets are off.
Good luck with your work - and if you are ever in the market for an upgrade, you’re in the right neighborhood. Cubase rocks!