ID 465254 - Thumbnails rendered from movs with an aspect ratio other than 1.77 will be one pixel higher in size than they should be

Problem summary
Thumbnails rendered from movs with an aspect ratio other than 1.77 will be one pixel higher than they should be.

Customer reported version
Flix 6.3.5

Steps to reproduce

1) In a Flix Show with aspect ratio other than 1.77, for example 2.39, import a still image into an empty Sequence Revision. 

2) Export the thumbnail (Image option from the Export popup) for this newly created panel.

3) Publish the one panel Revision to Editorial (eg Avid).

4) In Editorial, add an effect that doesn't change the image shape/size onto the panel, for example you can do a colour adjustment on the panel.

5) Publish back to Flix using Render All Frames, then export the thumbnail (Image option in the export popup) for the animated ref panel and compare it to the thumbnail exported in point 2.

Expected behaviour
Both thumbnails should be 1000x418 pixels.

Actual behaviour
Canvas size for the animated ref panel thumbnail is 1000x419 px, whereas the original panel thumbnail is 1000x418 px.

Reproduced by support

This bug has been reproduced in:
6.3.6 - macOS 10.14 Client - CentOS 7 Server

6.1.2 - Windows 10 Client - CentOS 7 Server

Earliest version tested
6.1.2 - This issue appears to be in all versions of the product