Bug report: 18.1.5 (Mega) Render hangs in Vegas Pro 21.0

On version 18.1.5 (Mega) render of a project in Vegas Pro 21.0 hangs forever. It hung two times in a row in the same position. On version 18.1.0 (Mega) the same project in Vegas Pro 21.0 was rendered successfully.

Do you have any proof that this problem was caused by K-Lite? And I mean actual proof, not just the fact that it was installed.

Because as far as I know Vegas does not even use DirectShow codecs.

On version 18.1.0 and earlier (all Mega) there were no such problems with render. It happened right after updating to version 18.1.5. And it was the only change between the previous successful render and these two hangs. And after downgrading to version 18.1.0 render was successful.
What sort of proof can I provide?

And how do you know it didn't fail because of some other reason? Doesn't it show any error with details about what failed?

Start by proving that Vegas actually uses any of the codecs from K-Lite.

It is fucking annoying that people always blame K-Lite, when they are using tools that does not even use the type of codecs that K-Lite installs.