It has not been possible to reproduce this issue even when running the app across multiple monitors at resolutions beyond 4K. But it was noted the application is using a large number of dynamic map service layers and is running as 'AnyCPU' with 'Prefer 32-bit' checked, which means it will always run as 32-bit and therefore can only access up to the 1.2GB memory limit of a 32-bit .NET process. The Prefer 32-bit checkbox should be unchecked.