We're using Umbracos "Nested Content" to build up pages.
Within the Nested Content, we have a document type, which consists of:

• "Richtext editor"-fields
• "Textstring"-fields
• "Numeric"-fields
• Etc. - but only "out-of-the-box" Umbraco-fields

We've noticed, that the value stored in "Richtext editor"-fields are sometimes deleted upon saving a page, making the "Richtext editor"-field empty next time the page is viewed in the backoffice, the "Richtext editor"-fields for the page are empty. The text is also deleted on the published version of the page.

For that reason, we upgraded from and older version of Umbraco 8, to Umbraco version 8.6.1, however the problem persists.

Does anyone else see the same problem, and does a workaround exist?

We havn't build any custom functionality to the backoffice for this website, so it's a pure Umbraco setup in the backoffice.