Index: src/wp-content/themes/twentynineteen/style-editor.scss
===================================================================
--- src/wp-content/themes/twentynineteen/style-editor.scss	(revision 51075)
+++ src/wp-content/themes/twentynineteen/style-editor.scss	(working copy)
@@ -478,6 +478,7 @@
 	}
 }
 
+.wp-block-pullquote[data-type="core/pullquote"],
 .wp-block[data-type="core/pullquote"],
 .wp-block[data-type="core/pullquote"][data-align="left"],
 .wp-block[data-type="core/pullquote"][data-align="right"] {
@@ -508,6 +509,12 @@
 	}
 }
 
+.wp-block[data-align="left"] .wp-block-pullquote,
+.wp-block[data-align="right"] .wp-block-pullquote {
+	text-align: inherit;
+	max-width: 50%;
+}
+
 .wp-block[data-type="core/pullquote"][data-align="left"],
 .wp-block[data-type="core/pullquote"][data-align="right"] {