In regards the 'TERM' environment variable; is that a new thing?

The variable itself is AFAIK not new, I think it's been around on *NIX systems for a long time, but not on Windows. But since many *NIX tools have been ported to Windows nowadays, they often still expect the common *NIX environment variables to be around.

I am pretty sure I didn't have 'dumb' set on those occasions.

I don't know, either the issue just didn't exist before, or it might have been set for you by a batch file like Strawberry Perl's portableshell.bat - in this node, Athanasius mentioned that Strawberry Perl 5.18.2 did set TERM=dumb, while 5.20.0 did set TERM=.