Index: src/wp-admin/css/media.css
===================================================================
--- src/wp-admin/css/media.css	(revision 49487)
+++ src/wp-admin/css/media.css	(working copy)
@@ -1183,6 +1183,10 @@
 	box-sizing: border-box;
 }
 
+.wp-core-ui .mejs-time {
+	box-sizing: content-box;
+}
+
 /* =Media Queries
 -------------------------------------------------------------- */