We recently upgraded from Magnolia 6.2.2 to Magnolia 6.2.3 which causes the break of the new Assets-App. When a new asset is uploaded the focalArea mgnl:contentNode is created but in addition since 6.2.3 there is a new node with an id and marked as type reference (see screenshot).

Error-Message:

java.lang.String cannot be cast to javax.jcr.Node. Stack trace: java.lang.ClassCastException: java.lang.String cannot be cast to javax.jcr.Nodejava.lang.String cannot be cast to javax.jcr.Node. Stack trace: java.lang.ClassCastException: java.lang.String cannot be cast to javax.jcr.Node at info.magnolia.dam.focal.area.field.FocalAreasFieldConverter.convertToPresentation(FocalAreasFieldConverter.java:43)

This causes the sub-app to crash, when we open an image because the module tries to load the contentNode but instead of the content node the reference not is used -> string ampping to a list.

Anothe issue is that the decorators are  breaking the app view. 
We have some custom fields like a damLinkField and we are also using the content tags module. This leads to not rendering the mentioned fields even if we provide them again in an decorator. After removing the dam focal module everything is working fine.

Also the UI of the Focal-Area tab isn't perfekt looking, huge pictures are using the whole screen.