Parsoid no longer provides the raw extension body text in body.extsrc and raw gallerycaption in data-mw='{"attrs":{"caption":""}}'. (Reference).
This change causes JS errors in MWGallery adaptation logic.
Error from logstash:
MT processing error for: gu > en. TypeError: Cannot read properties of undefined (reading 'split')
at MWGallery.adapt (/srv/service/lib/translationunits/MWGallery.js:16:51)
at Doc.adapt (/srv/service/lib/lineardoc/Doc.js:755:47)
at Adapter.adapt (/srv/service/lib/Adapter.js:25:27)
at /srv/service/lib/routes/v2.js:207:6
at runMicrotasks (<anonymous>)
at processTicksAndRejections (node:internal/process/task_queues:96:5)