1) Your audio isn't playing back in real time. This was added a couple minor versions back and I'm not a fan, but I understand the reasoning behind it. It at least keeps your audio in sync when your previews aren't able to play back in real time. If you want to revert to the previous behavior go to Preferences>Previews and check the box that says "Mute Audio When Preview Is Not Real-time"
2) Double-clicking on the Project panel opens the OS import dialog. For some reason the Options section which used to be opened up is now defaulted to closed. I asked about this and was told there was an OS change that was forcing this, and I believe a separate fix would have to be implemented, if it's possible. Anyway, double-click on the Project panel, go to the bottom left, click "Options" and then change the Import As option from Footage to Composition.
3) Can you post a screenshot or screen recording of this happening? For number 3 are both the keyframes Hold keyframes? Can you check the keyframe interpolation between the two keyframes where the movement is happening and see if it's set to anything other than Linear?
4) Can you post a screenshot or screen recording of this happening?
5) Are you exporting with a straight or premultiplied alpha?
Complete OS and AE version down to the last decimal point please. Workflow details would also help. I'm finding CC 2017 much more stable, easier to use and I'm more productive than I have been in a long time and I'm running it on the latest OSX on 3 different Macs from a Mac Book Pro R (late 2015) to a Mac Pro (Late 2008).
Are you still facing this problem? If not, let us know how you solved it. If so, please let us know so we can assist you further.