I guess the background task is the culprit. Background tasks set the default branch of `browser.cache.disk.enable` value to `false`. https://searchfox.org/mozilla-central/rev/64ddb621a0d3905fc2e3df475517d4163d377b22/toolkit/components/backgroundtasks/defaults/backgroundtasks.js#16 Even if users set the `browser.cache.disk.enable` value to `false`, the user-set value will be lost because the default value is the same as user-set one. Next time when Firefox launches normally, `browser.cache.disk.enable` value will be the default (that is, `true`).
Bug 1903580 Comment 8 Edit History
Note: The actual edited comment in the bug view page will always show the original commenter’s name and original timestamp.
I guess the background task is the culprit. Background task sets the default branch of `browser.cache.disk.enable` value to `false`. https://searchfox.org/mozilla-central/rev/64ddb621a0d3905fc2e3df475517d4163d377b22/toolkit/components/backgroundtasks/defaults/backgroundtasks.js#16 Even if users set the `browser.cache.disk.enable` value to `false`, the user-set value will be lost because the default value (`false` here) is the same as user-set one. Next time when Firefox launches normally, `browser.cache.disk.enable` value will be the default (that is, `true`).