diff --git a/CHANGELOG.md b/CHANGELOG.md
index 19dea5d4..1f5932d7 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -4,6 +4,12 @@ All notable changes to this project will be documented in this file.
 
 This projects adheres to [Semantic Versioning](https://semver.org/) and [Keep a CHANGELOG](https://keepachangelog.com/).
 
+## [13.1.1]
+
+### Fixed
+
+- Fixed `TailwindTrait::getTwClasses()` to skip `null` option values returned by `Helpers::checkAttr()` instead of passing them to `processOption()`, preventing a type error when an attribute is absent from the block attributes.
+
 ## [13.1.0]
 
 ### Fixed
@@ -1192,6 +1198,7 @@ Init setup
 - Gutenberg Blocks Registration.
 - Assets Manifest data.
 
+[13.1.1]: https://github.com/infinum/eightshift-libs/compare/13.1.0...13.1.1
 [13.1.0]: https://github.com/infinum/eightshift-libs/compare/13.0.0...13.1.0
 [13.0.0]: https://github.com/infinum/eightshift-libs/compare/12.3.4...13.0.0
 [12.3.4]: https://github.com/infinum/eightshift-libs/compare/12.3.3...12.3.4
diff --git a/src/Helpers/TailwindTrait.php b/src/Helpers/TailwindTrait.php
index d271ed92..0ffebfb1 100644
--- a/src/Helpers/TailwindTrait.php
+++ b/src/Helpers/TailwindTrait.php
@@ -472,6 +472,10 @@ public static function tailwindClasses(string $part, array $attributes, array $m
 		foreach ($options as $attributeName => $defs) {
 			$optionValue = Helpers::checkAttr($attributeName, $attributes, $manifest, true);
 
+			if ($optionValue === null) {
+				continue;
+			}
+
 			if (\is_bool($optionValue)) {
 				$optionValue = $optionValue ? 'true' : 'false';
 			}