Onlyoffice not working on iPad Pro / WebKit and Nextcloud 22

On iPad Pro and OnlyOffice + Community Document Server fails to open any larger document on WebKit based browser on iPad Pro. This has been confirmed on Nextcloud 20 and Nextcloud 22 (three different installations including fresh installation of Nextcloud 22), and on two different iPad devices.

Freshly installed Nextcloud, freshly installed Community Server and Onlyoffice connector. From Nexcloud apps store.

Spreadsheet or word document is stuck on ‘loading…’. At the beginning there is a spinning wheel and Loading … percent increases and then it gets stuck.

The behaviour is the same on ALL browsers on iPad pro as due to licencing issues ALL browsers on iPad are based on the same webkit engine.

There was a similiar bug for previous versions of OnlyOffice / Nextcloud.