diff --git a/classes/Bulk/Bulk.php b/classes/Bulk/Bulk.php
index 98e6cc08..19838714 100644
--- a/classes/Bulk/Bulk.php
+++ b/classes/Bulk/Bulk.php
@@ -594,18 +594,20 @@ public function bulk_get_stats_callback() {
 	 * @param array $old_value The old option value.
 	 * @param array $value The new option value.
 	 *
+	 * Please note that the convert_to_avif new value is a checkbox,
+	 * so it equals 1 when it's set otherwise it's not set.
+	 * That's why we need to use empty function when checking its value.
+	 *
 	 * @return void
 	 */
 	public function maybe_generate_missing_nextgen( $old_value, $value ) {
-		if ( isset( $old_value['convert_to_avif'] ) && isset( $value['convert_to_avif'] ) ) {
-			return;
-		}
-
-		if ( ! isset( $old_value['convert_to_avif'] ) && ! isset( $value['convert_to_avif'] ) ) {
+		if ( empty( $old_value['convert_to_avif'] ) === empty( $value['convert_to_avif'] ) ) {
+			// Old value = new value so do nothing.
 			return;
 		}
 
-		if ( isset( $value['convert_to_avif'] ) && ! (bool) $value['convert_to_avif'] ) {
+		if ( empty( $value['convert_to_avif'] ) ) {
+			// new value is disabled, do nothing.
 			return;
 		}