eglSwapBuffers called before eglStreamConsumerAcquireAttribNV leads to a deadlock

Subject is reproduced with example code (use latest master commit): GitHub - danvd/eglstreams-kms-example: Example of using EGLStreams + DRM KMS
eglStreamConsumerAcquireAttribNV is used in non-automatic mode.

Example prints message before calling eglSwapBuffers and after.
In my case with latest driver 470.63.01 the output looks like this:

Swap counter, begin: 1
Swap counter, end: 1
Swap counter, begin: 2
Swap counter, end: 2
Swap counter, begin: 3

After all the app hangs deep inside eglSwapBuffers and can only be killed.

Expected behavior: eglSwapBuffers flushes current GL pipeline (this may take sime time), switches buffers and returns, always.

This looks like a bug.
Maybe there is some workaround?

Anyway it’s better to correct this stuff :)