Puma was OS 10.0. Somebody at the bank is a tad behind the times.
Actually Puma was 10.1, released September 25, 2001. A mere 15 years ago. Good grief.
So Bruce - try logging into your bank using a different browser (I'd suggest Chrome - unless that's what you were using, of course) and see what it says. I'm wondering if it's some glitch in the browser. If it IDs the OS incorrectly in two different browsers, I'd suggest you let the bank know. There is something off on their end. It may have no effect on anything, but you also don't want to find yourself locked out some day because according to the bank you're not running a sufficiently secure browser/OS.
I think I will contact the bank about this. I was using Safari 10 (as I am now). I logged in using Firefox and got the same results.