Hi Phil,
in general, the different color gradient appearance can have several reasons, e.g.:
- using a reduced color format (e.g. RGB565 instead of RGB888)
- using a different display with lower color resolution (6 bit per color component instead of 8 bit)
- using a different LTDC color format setting
- hardware issues
Maybe you can try to place some color gradients into your application - as it is shown within the example 'ColorFormats' that is provided in all Build Environments.
In case of RGB888 / RGBA8888 it shoul look like this:

In case of RGB565 you will see color steps:

What do yo mean with "We have used this asset with EmWiz 8.3 on our custom hardware without issue."? Are you now using a different version?
Best regards,
Manfred Schweyer.