ID 519163 - When viewing H.264 files in Hiero or Nuke, frames will frequently be duplicated or dropped, resulting in the wrong frame being displayed in the Viewer

Problem summary
When viewing H.264 files in Hiero or Nuke, frames will frequently be duplicated or dropped, resulting in the wrong frame being displayed in the Viewer.
This has been tested with other codecs, such as ProRes and DNxHD, and the issue did not appear to occur with these files.
 
Customer reported version
Hiero 13.2v4
 
Customer reported platform
macOS
 
Steps to reproduce
 

Hiero:
1) In order to reproduce this issue, you will need an H.264 file.
An example file is attached, which was originally created in Nuke.
 
2) Open Hiero.
 
3) Import footage (File > Import  File(s)...)
 
4) Step forwards and backwards through the timeline, using the arrow keys, and notice that the Viewer will frequently display duplicate frames: 
 

 
However, the Viewer will sometimes 'drop' frames as well:
 

 

Nuke:
1) Open Nuke

 

2) Create a Read node and import the attached H.264 file

 

3) View the Read node, then Press and Hold the Right arrow key for a few seconds to skip many frames

 

4) Let go, then scrub backwards using the left arrow key, frames will have been skipped:
 

Expected behaviour
The Viewer should always display the correct frame.
 
Actual behaviour
When viewing H.264 files in Hiero or Nuke, frames will frequently be duplicated or dropped, resulting in the wrong frame being displayed in the Viewer.
 
Workaround
Unknown.
 
Reproduced by support
This bug has been reproduced in:
Hiero/Nuke 13.2v4 - Windows 10 - Linux CentOS 7 - Regression
 
Unable to reproduce bug in:
Hiero/Nuke 13.2v3 - Windows 10 - Linux CentOS 7
 
Earliest version tested
Hiero/Nuke 13.2v3 - This issue doesn't appear in this version and has regressed