BUG : Show project level in Ressource planning

Hello,

When you view "Resource Planning" with the "Show Project Level" option (access to additional settings), the project levels appear normally.

Then, if you collapse all the levels with the "-" button (Collapse all groups) and expand them with the "+" button (Expand all groups), the project levels appear briefly and then disappear.

This is not the case if you expand using the "+" button located next to the resource name. In this case, the projet levels appear normaly.

Version is 12.1.1.

Have a nice day,
Lionel