Fixing Preview Error when the url is invalid

app/src/main/java/com/vitorpamplona/amethyst/ui/components/UrlPreview.kt

@@ -19,10 +19,16 @@ import kotlinx.coroutines.withContext
 
 @Composable
 fun UrlPreview(url: String, urlText: String) {
-  val default = UrlCachedPreviewer.cache[url]?.let { UrlPreviewState.Loaded(it) } ?: UrlPreviewState.Loading
+  val default = UrlCachedPreviewer.cache[url]?.let {
+    if (it.url == url)
+      UrlPreviewState.Loaded(it)
+    else
+      UrlPreviewState.Empty
+
+  } ?: UrlPreviewState.Loading
   var context = LocalContext.current
 
-  var urlPreviewState by remember { mutableStateOf(default) }
+  var urlPreviewState by remember { mutableStateOf<UrlPreviewState>(UrlPreviewState.Loading) }
 
   // Doesn't use a viewModel because of viewModel reusing issues (too many UrlPreview are created).
   LaunchedEffect(url) {