This morning I had to upgrade from 220.127.116.1176 to 18.104.22.16829. We were unable to add new devices to a Hosted Probe Cluster Server. This was the remediation action recommended by Paessler. Shortly after upgrading my system, I started having probe health issues, specifically on my Hosted Probe Clustered servers (Master and Failover). I am looking at the historical "Open Requests" channel and I went from an average of about 17 - 30 messages open to well over 220 items open. I am seeing this behavior on both my Master and my Secondary. Is this a known issue? I've been running PRTG since version 17 and I have never seen this issue. If I expand my time frame out on my probe sensors to about 30 days, the average is around 19 open items. I haven't change the configuration since the upgrade/patch this morning.