diff --git a/Sources/Config.php b/Sources/Config.php
index f2082e4f8f..501e1afb08 100644
--- a/Sources/Config.php
+++ b/Sources/Config.php
@@ -1289,9 +1289,12 @@ public static function updateModSettings(array $change_array, bool $update = fal
 			return;
 		}
 
-		// Go check if there is any setting to be removed.
-		$to_remove = array_filter($change_array, fn($setting) => $setting === null);
-		$change_array = array_diff_key($change_array, $to_remove);
+		// Go check if there is any setting to be removed. The names are what we
+		// want here, not the nulls they are set to: {array_string:remove}
+		// binds the values, so handing it the whole array asks the database to
+		// delete every setting called ''.
+		$to_remove = array_keys($change_array, null, true);
+		$change_array = array_diff_key($change_array, array_flip($to_remove));
 
 		// Proceed with the deletion.
 		if (!empty($to_remove)) {
@@ -1302,6 +1305,15 @@ public static function updateModSettings(array $change_array, bool $update = fal
 					'remove' => $to_remove,
 				],
 			);
+
+			// The copy we are holding and the cached one both have to lose them
+			// as well. Otherwise the setting is still here for the rest of this
+			// request, and back again on the next one.
+			foreach ($to_remove as $variable) {
+				unset(self::$modSettings[$variable]);
+			}
+
+			Cache\CacheApi::put('modSettings', null, 90);
 		}
 
 		// In some cases, this may be better and faster, but for large sets we don't want so many UPDATEs.