*** Avisynth 3.71 final version has problems with prefetch and frame properties. ***
AvsPmod also reads the frame properties when creating a clip, so avisynth hangs.
There are two ways to avoid this:
Video > Display > YUV -> RGB > 'Read from source or script' must be disabled.
or
Use Avisynth version 3.72 test 1, the problem was fixed here.
This version is available on Doom9: https://forum.doom9.org/showthread.php?t=181351