Vk/GL external_memory texture sharing only working for some sizes

Hi All,

I am trying to use the external_memory extensions to share a VkImage into OpenGL.
This was working well, until I started to try and use non-power-2 texture sizes. At which point I started to get blank textures. And no warnings that I can see about API abuse.

(1) Is there a known limit on resourse sizes that are allowed when texture sharing?
(2) Which Vulkan functions and structures should I be using to obtain allowed sizes?
(3) All the samples I can find online all use power-of-2 fixed size textures, does anybody have any good examples of code that works with any size? This is particularly to get a Vulkan rendered viewport displayed using OpenGL.


Edit: Should have said, this is specifically on a Windows desktop machine.