Occasional failed to parse URL running from the web function runner

[coral apex]

On my dev server: dusty-caterpillar-550

I haven't upgraded yet.
Sometimes it works, sometimes I get:

info
'classifyWebsite2 called' 'https://www.puzzle-words.com/boggle-4x4/'
failure
Failed to parse URL from undefined/api/mutation

[limpid crag]

Could you share the source of classifyWebsite2?