I think the loops in RB have some issues. Here is something to try for yourself.
1. Start out new project. Make sure you have a style that has all real tracks in it selected.
2. Highlight one bar & right click on the highlighted bar and select & generate any loop.
3. Load in any loop & notice it will generate some Real Tracks and then generate the loop
4. Next start all over again with New and repeat except use a all MIDI style instead and notice this will only generate the loop and not several real tracks.
BIAB 2018 Ultrapack-Studio One Pro-Presonus Faderport-Presonus AudioBox iTwo
Windows 10 64bit 8gb