Reset the button block appearance.

shawburn/sass/_extra-child-theme.scss

@@ -239,6 +239,14 @@ hr.wp-block-separator.is-style-wide,
 /**
  * Blocks
  */
+
+// Button
+.entry-content > .wp-block-button:not(.alignleft):not(.alignright) {
+	margin-left: auto;
+	margin-right: auto;
+	text-align: center;
+}
+
 // Business Hours
 .jetpack-business-hours {
 	dt {

shawburn/style-rtl.css

@@ -4185,6 +4185,12 @@ hr.wp-block-separator.is-style-wide,
 /**
  * Blocks
  */
+.entry-content > .wp-block-button:not(.alignleft):not(.alignright) {
+	margin-left: auto;
+	margin-right: auto;
+	text-align: center;
+}
+
 .jetpack-business-hours dt {
 	font-family: inherit;
 	font-family: var(--font-base, inherit);

shawburn/style.css

@@ -4214,6 +4214,12 @@ hr.wp-block-separator.is-style-wide,
 /**
  * Blocks
  */
+.entry-content > .wp-block-button:not(.alignleft):not(.alignright) {
+	margin-left: auto;
+	margin-right: auto;
+	text-align: center;
+}
+
 .jetpack-business-hours dt {
 	font-family: inherit;
 	font-family: var(--font-base, inherit);