All of the kibana errors for the mirrored Parsoid/PHP language conversion endpoint specify
"exception_url": "/w/rest.php/zh.wikipedia.org/v3/transform/pagebundle/to/pagebundle/Main_Page
for example:
https://logstash.wikimedia.org/app/kibana#/doc/logstash-*/logstash-2019.12.03/parsoid-php?id=AW7L6Ynkh3Uj6x1zlmba&_g=h@44136fa
and
https://logstash.wikimedia.org/app/kibana#/doc/logstash-*/logstash-2019.12.03/parsoid-php/?id=AW7L1v1VarkxubcmmG7t
It would be helpful for debugging these errors to be able to reproduce them, and for that the actual page title would be very helpful.