And after closing the prompt with the render continuing, another one came up:
Internal error in NVIDIA AI Denoiser. Please report this to Corona support with this info:
Error encountered during denoising.
Unknown error (Details: Function "_rtCommandListExecute" caught exception: Assertion failed: "!m_launching : Memory manager launch is already active", file: C:\u\workspace\rel5.1-win64-cuda90-VS2015-build-Release\sw\wsapps\raytracing\rtsdk\rel5.1\src\Memory\MemoryManager.cpp, line: 962)
I have to add the AI denoiser works fine otherwise, no errors yet, that's the first time it happened.