%(error warning) is a string literal, so include? was doing a substring
test that would match any console type spelled inside it.

Assisted-by: Claude Opus 5 via Claude Code

diff --git a/lib/ketchup/snapshots.rb b/lib/ketchup/snapshots.rb
index 9e7259f..6b37cb3 100644
--- a/lib/ketchup/snapshots.rb
+++ b/lib/ketchup/snapshots.rb
@@ -452,7 +452,7 @@ module Ketchup
 
         yield
 
-        console_errors = @console_messages.select { %(error warning).include?(it[:type]) }
+        console_errors = @console_messages.select { %w[error warning].include?(it[:type]) }
 
         unless console_errors.empty? && @page_errors.empty?
           raise PageCheckError.new(