--- a/devtools/server/actors/stylesheets.js
+++ b/devtools/server/actors/stylesheets.js
@@ -153,17 +153,19 @@ function fetchStylesheetFromNetworkMonit
   if (!consoleActor) {
     return null;
   }
   const request = consoleActor.getNetworkEventActorForURL(href);
   if (!request) {
     return null;
   }
   const content = request._response.content;
-  if (request._discardResponseBody || request._truncated || !content) {
+  if (request._discardResponseBody || request._truncated || !content || !content.size) {
+    // Do not return the stylesheet text if there is no meaningful content or if it's
+    // still loading. Let the caller handle it by doing its own separate request.
     return null;
   }
 
   if (content.text.type != "longString") {
     // For short strings, the text is available directly.
     return {
       content: content.text,
       contentType: content.mimeType,