ID 394852 - Custom OCIO is causing small textures to export in full resolution

Problem summary
Custom OCIO is causing small textures to export in full resolution 

Customer reported version

Customer reported platform

Steps to reproduce

1) Create a new project using the aces OCIO config and one 16 bit, 4k channel filled with mid grey

2) Go to the channels palette and right click on the channel>Export Flattened>Export Current Channel Flattened 

3) In the export menu make sure to export the channel as EXR, enable Small Textures and remove Alpha Channels 

4) In the EXR preferences pop up window select the ZIP compression 

5) Check the resolution of the exported image in Nuke

result: the channel is exported in full resolution 

Expected behaviour
The channel to export in 8x8 resolution when any patches are filled with a constant color 

Actual behaviour
The channel is exporting at 4096x4096 resolution even though it is filled with a constant color 

Workaround
The issue does not occur with nuke-default and patches filled with black

Reproduced by support
This bug has been reproduced in:

4.5v1 - Windows 10 - CentOS 7

4.0v1 - Windows 10 - regression

Unable to reproduce bug in:
3.4v4 - Windows 10 - CentOS 7 - OSX 10.13.6

Earliest version tested
3.4v4 - This issue no longer appears in this version and has regressed