Index: wp-content/themes/twentyseventeen/assets/css/editor-blocks.css
===================================================================
--- wp-content/themes/twentyseventeen/assets/css/editor-blocks.css	(revision 58682)
+++ wp-content/themes/twentyseventeen/assets/css/editor-blocks.css	(working copy)
@@ -527,7 +527,7 @@
 	display: block;
 	font-size: inherit;
 	font-style: normal;
-	font-weight: 600;
+	font-weight: inherit;
 	margin-top: 0.5em;
 }
 
Index: wp-content/themes/twentyseventeen/style.css
===================================================================
--- wp-content/themes/twentyseventeen/style.css	(revision 58682)
+++ wp-content/themes/twentyseventeen/style.css	(working copy)
@@ -517,10 +517,11 @@
 
 blockquote cite {
 	display: block;
-	font-style: normal;
-	font-weight: 600;
 	margin-top: 0.5em;
 }
+.wp-block-quote cite{
+	font-style: inherit;
+}
 
 address {
 	margin: 0 0 1.5em;