Index: src/wp-content/themes/twentynineteen/style-rtl.css
===================================================================
--- src/wp-content/themes/twentynineteen/style-rtl.css	(revision 55880)
+++ src/wp-content/themes/twentynineteen/style-rtl.css	(working copy)
@@ -5889,7 +5889,7 @@
 
 @media only screen and (min-width: 768px) {
   .entry .entry-content .wp-block-image .aligncenter {
-    margin: 0;
+    margin: 0 auto;
     width: calc(8 * (100vw / 12) - 28px);
   }
   .entry .entry-content .wp-block-image .aligncenter img {
Index: src/wp-content/themes/twentynineteen/style.css
===================================================================
--- src/wp-content/themes/twentynineteen/style.css	(revision 55880)
+++ src/wp-content/themes/twentynineteen/style.css	(working copy)
@@ -5901,7 +5901,7 @@
 
 @media only screen and (min-width: 768px) {
   .entry .entry-content .wp-block-image .aligncenter {
-    margin: 0;
+    margin: 0 auto;
     width: calc(8 * (100vw / 12) - 28px);
   }
   .entry .entry-content .wp-block-image .aligncenter img {