CSP field "loading" when attempting certificate request on internal PKI issuing CA

We're having a browser problem with our internal PKI.  When we request a new certificate from our Issuing CA (W2K12R2) via a browser (using Firefox or IE) the CSP field never populates - sticking on "loading".  It doesn't matter which certificate template I choose.  

We already have "Display intranet sites in Compatibility View" enabled in IE.  So the tip I found in a similar conversation isn't working for us..  

If I use the Certificates MMC console, I can request the certificate and see the CSP's on the "Private Key" tab.  I have not completed a certificate request using the MMC b/c we really want the browser method to work b/c it will be much easier for our end users to navigate the browser interface.

I don't believe our internal PKI has always behaved this way.  I know we've requested certificates in the past via the browser. The problem is that it's been quite a while since anyone has needed to manually request a certificate this way.  It just doesn't happen that often.

Tried an IISRESET + Certificate Services stop-n-start on the issuing CA.  But it did not make a difference.