Values set with GM.setValue are not in storage.

At this part:
https://github.com/Purfview/IMDb-Scout-Mod/blob/5881b5bbf67e26c69945e381959eeaaf73a770c9/IMDb_Scout_Mod.user.js#L9761-L9763

Windows 10 tests:
Opera: Both Tampermonkey(5.3.3) & Violentmonkey(2.31.0) works.
Firefox: Tampermonkey(5.3.3) works, Violentmonkey(2.31.0) not working.

Last working Violentmonkey version: v2.19.0.
Starting from v2.19.3, it doesn’t work anymore. [probably since v2.19.1 - untested ]

Originally reported there: Purfview/IMDb-Scout-Mod#288