The adf-content-metadata-card component gives an error in ADF 2.5 and 2.6, I get the error after generating a new ADF app with Yeoman, opening a document preview, opening the 'info' sidebar and selecting 'Properties'.
The error message that I get:

It seems to be an error on the mat-expansion-panel-header tag in the contentMetadata component html. Does this have to do with the version of Angular Material used (6.4.3)?