If you duplicate the y-axis, you'll get a broken copy of the y-axis
If you duplicate the y-axis, you'll get a broken copy of the y-axis, i.e. it doesn't behave as a regular axis object. It seems to be only an unmovable text (see the attached image). After reopening the project's file, the name of the duplicated y-axis ("Speed") disappeared. Perhaps the same applies to the x-axis.
See the attached project's file: duplicated_y.lml
Edited by Dariusz Laska