Water setting: Blur Multiplier not applying negative values

[AtlasLinden]

Environment

Second Life Release 7.1.12.13509103967 (ForeverFPS)

Description

Blur Multiplier now works in the latest ForeverFPS build!
However, negative values that used to work in pre-PBR viewers are no longer being applied. But positive values do.
Please see the following clips showing the differences spotted.

ForeverFPS (7.1.12.13509103967): https://gyazo.com/949c56d146805e4c34431c5b5abb56c4
Pre-PBR (6.6.16.6566955269): https://gyazo.com/63520e5be7425dd179f839051dd691c8

Reproduction steps

Open Library sky setting A-6PM
Also open the default water setting
Point camera towards the sunset
Move the Blur Multiplier in the water setting

[kylelinden]

Expected behavior. Will however create a UX issue to clamp values.