Certainly seems to be. The higher the multiplier is, the quicker it'll crash.
I'd hesitate to call it an immediate memory leak. More along the lines of so many different sprites caching, because it's
AEons of Death. And there are many...
many sprites.
Furthermore I have a WIP addon included which includes some larger sprites (all of which I plan on compressing the sprite file sizes as soon as I'm happy with all of them and they don't need further changes done to them). The monsters in question have 16 sprite angles too. The strange thing is, OpenGL never has this issue. Ever. This makes the vulkan situation all the more bizarre...
I think at this stage, unless you have any other ideas, it may be time for a last resort. If you and/or _mental_ are ready and willing to try and trace it yourselves, I'll send you all the files in a bundle. I'll see about including a simple "LoadMe.pk3" file with GameInfo set up to load all the files for you to make this as smooth as possible for you.
I'll ensure everything's set up so you don't have to change any of the mod's options around to get the effect to replicate. All you'll have to do is start the game, attach the debugger and wait patiently for it to crash - which shouldn't take long at all.