Describe the bug

When using vue-class-component BCard and BCardBody render content as undefined.
The issue has been previously reported here and fixed here, but later on this commit got it broken again.

Steps to reproduce the bug

The issue appears when using mixed components with @Component decorator and without it.

Expected behavior

Expected to work properly

Versions

Libraries:

• BootstrapVue: 2.21.2
• Vue: 2.5.17, 2.6.14