Crg
The bugs and flaws are mearly a lack of understanding of what's going on on the technical data side. You're going to have to figure it out whether you change DAW hosts or not.
Plus One to that. Don't get me wrong Scobrea, I'm sure Cubase is entirely capable, but Crg has a point there. Each of the high end DAWs, and I include X1 in that statement, all need a bit of patience while you learn all that you need to create your projects.
Would it be possible to make a copy of your project? The reason I say that is, if it is a large project, with the copy, you can delete the audio, which will not be causing the tempo change issue, and then save that and upload it somewhere. I will then have a look at it for you.
cheers
andy