App hangs on second xrBeginFrame call

Hi,

I’m working on integration of a Vulkan-based engine with OpenXR for a uni project. I’m at the stage where I’m trying to render frames to the headset and have all the code for this in place. I’m working on an HTC Vive and SteamVR as OpenXR runtime. When I run the frame loop without drawing frames, the app loads in the headset, the frame loop keeps running, and the screen is blank - as expected. However, when I try to draw a frame, the app doesn’t return from the next xrBeginFrame call. The headset just gets stuck in the Steam loading state of the “mountains scene”. Does anyone have any pointers to what might cause such behavior?

I have no previous experience with either Vulkan or OpenXR, so I’d appreciate any help in getting this to work. Seems that I’m finally close! Let me know if any more information is needed. There’s so much code that I’m not sure what to include. My app is based on the hello_xr example with some differences.

Edit:
I get this in debug console:

Fri Apr 30 2021 14:19:29.188 - Created shared texture ‘Scene create Vulkan, 0’ 1852x2056 (1 mips)
Fri Apr 30 2021 14:19:29.189 - Created shared texture ‘Scene create Vulkan, 0’ 1852x2056 (1 mips)
Fri Apr 30 2021 14:19:29.192 - Created shared texture ‘Scene create Vulkan, 1’ 1852x2056 (1 mips)
Fri Apr 30 2021 14:19:29.193 - Created shared texture ‘Scene create Vulkan, 1’ 1852x2056 (1 mips)
Fri Apr 30 2021 14:19:29.196 - Application submitted two left scene textures for a single frame!
Fri Apr 30 2021 14:19:29.196 - Application submitted two right scene textures for a single frame!

“Application submitted two left scene textures for a single frame!” I could not find any information on this warning online. Could the above point to anything?