--- a/services/healthreport/providers.jsm
+++ b/services/healthreport/providers.jsm
@@ -984,17 +984,17 @@ AddonsProvider.prototype = Object.freeze
       counts: {}
     };
 
     for (let addon of addons) {
       let type = addon.type;
 
       // We count plugins separately below.
       if (addon.type == "plugin") {
-        if (addon.gmPlugin) {
+        if (addon.isGMPlugin) {
           data.gmPlugins[addon.id] = {
             version: addon.version,
             userDisabled: addon.userDisabled,
             applyBackgroundUpdates: addon.applyBackgroundUpdates,
           };
         }
         continue;
       }