Backed out changeset a2a3d6bf518f (bug 1921060) as requested for causing multiple regressions.

browser/components/sessionstore/SessionStore.sys.mjs

@@ -3170,6 +3170,7 @@ var SessionStoreInternal = {
    *        Tab reference
    */
   resetBrowserToLazyState(aTab) {
+    const gBrowser = aTab.ownerGlobal.gBrowser;
     let browser = aTab.linkedBrowser;
     // Browser is already lazy so don't do anything.
     if (!browser.isConnected) {
@@ -3183,6 +3184,7 @@ var SessionStoreInternal = {
     this._lastKnownFrameLoader.delete(browser.permanentKey);
     this._crashedBrowsers.delete(browser.permanentKey);
     aTab.removeAttribute("crashed");
+    gBrowser.tabContainer.updateTabIndicatorAttr(aTab);
 
     let { userTypedValue = null, userTypedClear = 0 } = browser;
     let hasStartedLoad = browser.didStartLoadSinceLastUserTyping();
@@ -4922,6 +4924,7 @@ var SessionStoreInternal = {
       );
     }
 
+    const gBrowser = aTab.ownerGlobal.gBrowser;
     let browser = aTab.linkedBrowser;
     if (!this._crashedBrowsers.has(browser.permanentKey)) {
       return;
@@ -4941,6 +4944,7 @@ var SessionStoreInternal = {
     // a flash of the about:tabcrashed page after selecting
     // the revived tab.
     aTab.removeAttribute("crashed");
+    gBrowser.tabContainer.updateTabIndicatorAttr(aTab);
 
     browser.loadURI(lazy.blankURI, {
       triggeringPrincipal: Services.scriptSecurityManager.createNullPrincipal({