SSL cert expiration date not refreshing

I recently renewed some SSL certs for our domain.  Xymon was testing the https addresses and was correctly showing the ciphers and expiration date.  But after I renewed and applied the certs to our servers Xymon still shows the old expiration date, not the new one.  The SSL certs were applied correctly to our servers and all browsers and external tests show accurate dates, but not Xymon.  Any idea why this would occur?  Https server is running IIS 8.5