If you set ComponentClass override in child class BP and grandchild class BP respectively, it is ignored in grandchild class.
This issue is probably related to [Link Removed]. The fix for [Link Removed] solved the issue for child class BP, but it doesn't seem to consider grandchildren and beyond.
expect : print "BP_Component_Child "
result : print BP_Component"
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-178121 in the post.