Hello,
It doesn't work because the path to the template isn't quite right
You use a linux-style relative directory path to point to your templates. In your case, if you are trying to access:
/apps/myprj1/core/components/content/templates/templatesA.html
from
/apps/myprj1/core/components/content/componentA/componentA.html
Then the relative path is:
../templates/templatesA.html
Try using that instead
I reproduced it on my instance using this fix:

