Hi Iiro,
What is puzzling about this problem however, is that none of my query components seem to be listed as 'not supported'.
But one particular 'not supported' element which is a bit of a question mark is:
| Custom Structures | Limited | Only Keyfigure based structures are supported. Structures based on characteristics are not supported. |
Does this mean that if I have a structure on the columns for example, it can only contain key figures and no characteristic restrictions? If this is the case, this is a rather huge limitation.
My variables are actually all optional selections, which are a mix of standard business content and some custom ones. A few are created on authorization-relevant info-objects.
I will modify my query to test different scenarios, but it would be good to get a comment from SAP 
EDIT: I have made changes to my BEx Query to dumb it down to a very bare-bones version but the Lumira Desktop scheduling to Cloud is still giving the same error message
/Karri