It never fails to catch newbies to this UI out, regardless of the model.
So you would say this is not a bug?
The Menu Hide feature works just as it should.
It takes a good while to get to know and learn all the features in these scopes where working through the OM and experimenting with settings can help to understand how it all has been designed as it is.
Eg, a very experienced and capable user might have the Menu Hide feature set to 3s, the minimum, whereas this setting would drive others to despair.
Others of us that have worked with this UI for some years know how the scopes work and appreciate why they have been configured as they are.
However any bug that can be faithfully and repeatedly reproduced after first a Default then set the unit for your needs should be reported here along with SW version and when possible accompanying screenshots that display settings.
Complex bugs can also be better identified/reproduced with a Setup file for anyone to configure the scope as you might have it and see what is not always a bug.