--- a/toolkit/components/telemetry/TelemetryEnvironment.jsm
+++ b/toolkit/components/telemetry/TelemetryEnvironment.jsm
@@ -507,17 +507,17 @@ EnvironmentAddonBuilder.prototype = {
         () => this._shutdownBlocker());
     } catch (err) {
       return Promise.reject(err);
     }
 
     this._pendingTask = (async () => {
       try {
         // Gather initial addons details
-        await this._updateAddons();
+        await this._updateAddons(true);
 
         if (!this._environment._addonsAreFull) {
           // The addon database has not been loaded, so listen for the event
           // triggered by the AddonManager when it is loaded so we can
           // immediately gather full data at that time.
           await new Promise(resolve => {
             const ADDON_LOAD_NOTIFICATION = "xpi-database-loaded";
             Services.obs.addObserver({
@@ -622,33 +622,37 @@ EnvironmentAddonBuilder.prototype = {
   },
 
   /**
    * Collect the addon data for the environment.
    *
    * This should only be called from _pendingTask; otherwise we risk
    * running this during addon manager shutdown.
    *
+   * @param {boolean} [atStartup]
+   *        True if this is the first check we're performing at startup. In that
+   *        situation, we defer some more expensive initialization.
+   *
    * @returns Promise<Object> This returns a Promise resolved with a status object with the following members:
    *   changed - Whether the environment changed.
    *   oldEnvironment - Only set if a change occured, contains the environment data before the change.
    */
-  async _updateAddons() {
+  async _updateAddons(atStartup) {
     this._environment._log.trace("_updateAddons");
     let personaId = null;
     let theme = LightweightThemeManager.currentTheme;
     if (theme) {
       personaId = theme.id;
     }
 
     let addons = {
       activeAddons: await this._getActiveAddons(),
       theme: await this._getActiveTheme(),
-      activePlugins: this._getActivePlugins(),
-      activeGMPlugins: await this._getActiveGMPlugins(),
+      activePlugins: this._getActivePlugins(atStartup),
+      activeGMPlugins: await this._getActiveGMPlugins(atStartup),
       activeExperiment: {},
       persona: personaId,
     };
 
     let result = {
       changed: !this._environment._currentEnvironment.addons ||
                !ObjectUtils.deepEqual(addons, this._environment._currentEnvironment.addons),
     };
@@ -746,22 +750,27 @@ EnvironmentAddonBuilder.prototype = {
       };
     }
 
     return activeTheme;
   },
 
   /**
    * Get the plugins data in object form.
+   *
+   * @param {boolean} [atStartup]
+   *        True if this is the first check we're performing at startup. In that
+   *        situation, we defer some more expensive initialization.
+   *
    * @return Object containing the plugins data.
    */
-  _getActivePlugins() {
+  _getActivePlugins(atStartup) {
     // If we haven't yet loaded the blocklist, pass back dummy data for now,
     // and add an observer to update this data as soon as we get it.
-    if (!Services.blocklist.isLoaded) {
+    if (atStartup || !Services.blocklist.isLoaded) {
       if (!this._blocklistObserverAdded) {
         Services.obs.addObserver(this, BLOCKLIST_LOADED_TOPIC);
         this._blocklistObserverAdded = true;
       }
       return [{
         name: "dummy", version: "0.1", description: "Blocklist unavailable",
         blocklisted: false, disabled: true, clicktoplay: false,
         mimeTypes: ["text/there.is.only.blocklist"],
@@ -798,25 +807,30 @@ EnvironmentAddonBuilder.prototype = {
       }
     }
 
     return activePlugins;
   },
 
   /**
    * Get the GMPlugins data in object form.
+   *
+   * @param {boolean} [atStartup]
+   *        True if this is the first check we're performing at startup. In that
+   *        situation, we defer some more expensive initialization.
+   *
    * @return Object containing the GMPlugins data.
    *
    * This should only be called from _pendingTask; otherwise we risk
    * running this during addon manager shutdown.
    */
-  async _getActiveGMPlugins() {
+  async _getActiveGMPlugins(atStartup) {
     // If we haven't yet loaded the blocklist, pass back dummy data for now,
     // and add an observer to update this data as soon as we get it.
-    if (!Services.blocklist.isLoaded) {
+    if (atStartup || !Services.blocklist.isLoaded) {
       if (!this._blocklistObserverAdded) {
         Services.obs.addObserver(this, BLOCKLIST_LOADED_TOPIC);
         this._blocklistObserverAdded = true;
       }
       return {
         "dummy-gmp": {version: "0.1", userDisabled: false, applyBackgroundUpdates: true}
       };
     }