Dimension settings are saved with each View. So, you must be switching to a view that has a different setting.

You will not the word 'custom' in your screenshot. Once you set up all of the dimension preferences to your desire for the project, or for particular views, save those settings with a NAME. (Click the "Add..." button. You "never" want to save the word "custom" for any aspect of any saved view - you'll have no idea what is associated with the view.)

Now, redefine your views with the defined dimension setting name, and your fractions will always appear with those views ...and any placed drawings based on those views.

Cheers,
Karl