Index: wp-content/themes/twentynineteen/sass/blocks/_blocks.scss
===================================================================
--- wp-content/themes/twentynineteen/sass/blocks/_blocks.scss	(revision 54300)
+++ wp-content/themes/twentynineteen/sass/blocks/_blocks.scss	(working copy)
@@ -171,7 +171,7 @@
 			border: none;
 			font-size: $font__size-sm;
 			@include font-family( $font__heading );
-			line-height: $font__line-height-heading;
+			line-height: inherit;
 			box-sizing: border-box;
 			font-weight: bold;
 			text-decoration: none;
Index: wp-content/themes/twentynineteen/style-editor.scss
===================================================================
--- wp-content/themes/twentynineteen/style-editor.scss	(revision 54300)
+++ wp-content/themes/twentynineteen/style-editor.scss	(working copy)
@@ -381,7 +381,7 @@
 .wp-block-button {
 
 	.wp-block-button__link {
-		line-height: 1.8;
+		line-height: inherit;
 		@include font-family( $font__heading );
 		font-size: $font__size-sm;
 		font-weight: bold;