Legacy bump breaking change under PBR/ForeverFPS

[canny]

Location to reproduce:

http://maps.secondlife.com/secondlife/Han%20Loso/72/190/59

Steps to reproduce:

1. Touch 3-4 perimeter buttons on the circular dialing control in front of the gate.

2. Observe the illuminated chevrons on the gate ring itself

This bug seems to present on fullbright surfaces using the legacy bumpiness options.

I've isolated the component of the object that demonstrates this bug and attempted setting it to bumpiness:none and back to bumpiness:bark as it should have, and it looks much better. Changing my selection away from the item however makes it revert to the broken state.

Items should not change how they look based on if they are selected or not, and legacy content should not look this different, the right example in my isolated example screenshot is completely acceptable if it can be achieved without it resetting on de-selection.

Additional wacky aspect of this comes in when scaling the item: https://youtu.be/qB7tVtKFMOQ

This scaling issue does not at-all repro on FS 6.x

https://secondlife.canny.io/admin/board/bug-reports/p/legacy-bump-breaking-change-under-pbr-foreverfps

[canny]

This issue has been linked to a Canny post: Legacy bump breaking change under PBR/ForeverFPS 🎉

[AtlasLinden]

A repro can be obvious when turning on Full Bright with an object using a bump map.
Although this only appears to remain until the camera is moved: https://gyazo.com/c873e3265ed2f95d23ce8bff48672f8a
However, the use case presented by the reporter is in relation to an object changing state via a script.

This behaviour also reproduces upon scaling the object.