Fixed Version! Rated 5 out of 5 stars

@John - Sometimes Firefox Wouldn't take corrections maket direct from about:config, when FF is Open.
I don't know Why is happening this but I can suggest You and all users on this wonderful addon the solution on problem, where you writed for.
The Reason switch-to-tab Blacklist to reset in to him original settings is causes, 'cause source code of bootstrap.js located in to switch_to_tab_blacklist-1.1-fx.xpi contains code, witch no working correct.
The original source code on bootstrap.js contains code looke like this on paragraphs from 41 to 46:

--------------------------------------------------------------

const DEFAULT_BLACKLIST = [
"http://maps.google.com/"
];
const DEBUG = false;

let gBlacklist = []; [/code]

--------------------------------------------------------------

After maked from Me corrections the source code in this sector on bootstrap.js look like this:

--------------------------------------------------------------

const DEFAULT_BLACKLIST = [
".*"
];
const DEBUG = false;

let gBlacklist = [".*"];[/code]

--------------------------------------------------------------

If you wanna make switch-to-tab Blacklist to prevent the reset settings, after Upgrade of FF Version,
execute following manipulations:
1. Uninstall switch-to-tab Blacklist and close Firefox.
2. Find in %appdata%\Mozilla\firefox\Profiles\Your_profile\extensions switchToTabBlacklist@zpao.com.xpi and delete him.
3. Find the prefs.js and delete all paragraphs witch contains extension.switchToTabBlacklist.blacklist and save prefs.js.
4. After this Download the edited version of switch-to-tab Blacklist from http://www.multiupload.com/ZTK3R7MFWW and Install it.

Hope that my post is useful for all users likes switch-to-tab Blacklist

Not recommended

I don't suggest this at all. If you replace the version you installed from here with a 3rd party one, you won't receive updates.

The dataloss issue is either a bug with the addon or a bug with Firefox.