I found the solution in neoseeker website and posting it here.
Save the game before the buggy cutscene. Open console with ~ tilde key. Enter
ai_norebuildgraph "0"
Return to game and the game will continue. If fails retry again as it worked 2nd time in my case.
This is probably due to some animation related event and something in the script of Radek model. Valve engine generates path from where a model will move and may be this is where the bug is.
More information is available here -
