Users often report that the GPS maps are missing when importing workouts to RunGap and therefore also missing when sharing these workouts to other services.
In many cases the problem is caused by RunGap fetching the workouts indirectly from "Health" rater than the original service.
You can check if the workouts come from Health by opening it in RunGap and look at the "Source" listed at the bottom of the page. To avoid importing workouts from Health you must open Health from "Accounts & Settings" and make sure that importing is disabled.
After disabling import from Health (which is the default settings) you can delete the affected workouts and then do a "Resynchronize Activities" for the original service to fetch fresh copies. The "Filter" function in the Activities can be used to display only the workouts imported from Health.
If you are wondering why GPS Maps are not included in Health you can find more information here.