cable tray slope
If 2 cables trays are joined and they have a slight difference in offset height REVIT automatically adds a slope to enable them to join, this is causing endless problems. As more and more cable tray is joined onto the system and along various points where the slope has been created it then adds more slopes to compensate so one end of the cable tray system can be completely different offset to the other. Revit should not automatically add a slope onto something that is rarely installed with a slope. There should be a warning at least that a slope will be added or should not let you join unless both sections are at the same offset, adding a slope should be a user defined option for the rare occasions you require one.