Our Jura J5 does not perform the self rinse when you turn it off like the manual states.

SOURCE: The tray (JURA J5) keeps indicating that it needs

The connectors at the back have liquid on them use a lint free cloth to remove the liquid and the tray fault will go away. If you want to prevent this make sure that when you pour the water out the tray you pour it out the side not the back and this is how the liquid or debris gets stuck there

SOURCE: The tray (JURA J5) keeps indicating that it needs

I had the same problem. After trying everything on this site from cleaning contacts with a fine 1000 steel wool, to filing down the inner contacts with an emery board, nothing worked. Finally I rinsed the tray contacts under pressure, dried them and inserted the tray back. The coffee machine started the cleaning process again and it finished.

I think the problem was emptying the dirty water in the tray through the back instead of the front; something must have gotten stuck within the contacts and caused the problem.

SOURCE: Whether I turn the Jura z5 off manually or let it

I have exactly the same problem, did you ever solve yours?