Mikael Abrahamsson wrote:

I will not make any more recommendations on how to proceed with this, it
sounds like failing sdbt houldn't be needed and if I were you, I would
assemble the array, keep it running until someone else who knows more
can potentially help you with what might be wrong with your older
version of mdadm (or the newer one might not do everything it should, or
it's something your kernel is doing wrong).

Understood.  Many thanks again for the assist!!!  I'm certainly intent
on rolling out a newer version of mdadm now..will proceed on that
endeavor with prudent caution.