diff --git a/components/style/properties/declaration_block.rs b/components/style/properties/declaration_block.rs
index 5dc5d207f36..75d05836972 100644
--- a/components/style/properties/declaration_block.rs
+++ b/components/style/properties/declaration_block.rs
@@ -1347,7 +1347,6 @@ impl<'a, 'b, 'i> DeclarationParser<'i> for PropertyDeclarationParser<'a, 'b> {
         let id = match PropertyId::parse(&name, self.context) {
             Ok(id) => id,
             Err(..) => {
-                self.last_parsed_property_id = None;
                 return Err(input.new_custom_error(StyleParseErrorKind::UnknownProperty(name)));
             },
         };
@@ -1469,6 +1468,10 @@ pub fn parse_property_declaration_list(
         match declaration {
             Ok(importance) => {
                 block.extend(iter.parser.declarations.drain(), importance);
+                // We've successfully parsed a declaration, so forget about
+                // `last_parsed_property_id`. It'd be wrong to associate any
+                // following error with this property.
+                iter.parser.last_parsed_property_id = None;
             },
             Err((error, slice)) => {
                 iter.parser.declarations.clear();