ID 425814 - VectorDistort outputting st-map inverse maps are 1 pixel off on the reference frame

Problem summary
VectorDistort outputting st-map inverse maps are 1 pixel off on the reference frame

Customer reported version
nuke.12.0v3

Customer reported platform
centos7

Steps to reproduce

1) Open attached Nuke script

2) Zoom in to a corner, so you can see pixels

3) Toggle the STMap node on and off

Expected behaviour
For the st-map inverse to make no differnce when viewing the reference frame.

Actual behaviour
There is a 1 pixel discrepancy:

​

Workaround
Unknown.

Reproduced by support

This problem has been reproduced on:

Nuke 12.0v5 - Windows 10 - CentOS 7.7 - MacOSX 10.13

Nuke 12.0v1 - Windows 10

Nuke 11.2v1 - Windows 10 - CentOS 7.7 - MacOSX 10.13 - regression

Unable to reproduce bug in:
Nuke 11.1v6 - Windows 10 - CentOS 7.7 - MacOSX 10.13

Earliest version tested
Nuke 11.1v6 - This issue doesn't appear in this version and has regressed