OK so this has to do with trying to run solr service as windows domain
user. It works w/o problems (fingers crossed) when run as "LocalSystem"
account, runs into this core reloading loop when run as a domain users,
and giving the domain user "full control" on solr directory tree does
not fix that.
It's a good thing we're changing providers and will soon be able to
ditch windows for at least solr. We hope.