When I enter a destination on the MRA Android app and select the allow Highways option

For me this means a simple A > B route from your location to a destination
To do this I would select "Destination" from the route options draw,
Search for & then select my destination, followed by pressing the Navigate button & my route options would be shown

As you can see when select Leicester as my destination from west London it definitely allows me to use motorways / highways as it gives me the choice of routing via the M1 or M40
Under "Avoidance options" the "Highways" button is the default green as an allowed road

I think to help further you will need to explain your steps a bit more fully

To just get to your destination (again could be controlled by avoidances), try using the option "MRA Routeplanner / Create new routes".
It uses Highways then.

Thanks for taking the time to reply.

I sense I'll be using MRA for route planning for motorcycle tours but will have to stick with Waze if I just want navigation to a single destination. Shame as I paid for lifetime membership

@Mark-Williams-5-0 said:
The allow Highways options will be toggled off again when I check. I toggle it on, app still won't navigate using highways and when I look at the routing options again, allow Highways will be toggled off.

This is definitely not normal behaviour if your just selecting "Destination" from the route options draw in the app & choosing a place to navigate too
It sounds like the "Avoidance Option - Highways" setting has become fixed rather than selectable
Have you tried toggling any of the other avoid options to see if they also reset?

You could try force stopping the app to see if that resets anything or maybe try logging in/out of the app to see if that clears something

https://www.myrouteapp.com/support

The MRA Navi app routes on the highway if you want it, the settings may not contradict each other