Index: wp-content/themes/twentynineteen/sass/blocks/_blocks.scss
===================================================================
--- wp-content/themes/twentynineteen/sass/blocks/_blocks.scss	(revision 55900)
+++ wp-content/themes/twentynineteen/sass/blocks/_blocks.scss	(working copy)
@@ -173,7 +173,7 @@
 			@include font-family( $font__heading );
 			line-height: $font__line-height-heading;
 			box-sizing: border-box;
-			font-weight: bold;
+			font-weight: inherit;
 			text-decoration: none;
 			padding: ($size__spacing-unit * .76) $size__spacing-unit;
 			outline: none;