Today, I can into the same error: "invalid device load executing vertex function". I'm using a GPU kernel to encode draw calls. After reading this thread, the solution turned out to be to run the app under a different scheme. So, yes, as Stan has mentioned earlier, this error might be related to shader compilation. Actually, throughout the day I saw Xcode recompiling parts of the codebase, even though I hadn't touched any code between runs. Something I've never seen it do. I do have to mention that the Xcode schemes are managed by AppCode (JetBrains) so there might be some incompatibility here. Having said that, the Xcode/AppCode combination has always worked fine for me.

ICB shader debugging is currently not available, AFAIK. Enabling shader validation might help somewhat: MTL_SHADER_VALIDATION_GPUOPT_ENABLE_INDIRECT_COMMAND_BUFFERS=1 See this issue for more info.