Steps to reproduce

1. In a magnolia 6.2.6 + Blossom 3.4.4 (old pages app) .Set up sample blossom in your project
2.  Modify a component and include (for instance, info.magnolia.blossom.sample.module.templates.components.BookCategoryComponent)

    @TabFactory("tab.node.label")
       public void createNodeTab(UiConfig cfg, TabBuilder tab, Node node) throws RepositoryException {
            StaticFieldBuilder sfb = cfg.fields.staticField("nodePath");
   	 sfb.definition().setValue(node.getPath());
   	 tab.fields(sfb);
       }
   

3. Go to legacy pages app, open a page and add the component.
4. Go to resources app and open it (everything works as expected).
5. Migrate to 6.2.7
6. Go to Legacy pages app and open a page and add the component
7. Go to Resources app

Expected results

Resources app works as expected

Actual results

Resources app is not working at all ( Blossom-ResourcesApp-Error.txt ):

Workaround

Do no migrate to 6.2.7

Development notes

Only happens after 6.2.7, might be related to the change in the vaadin version (BUILD-441) . Most likely related also to BLOSSOM-276.