Here are some answers to your questions.
1. Have you always seen this issue, or did this issue recently start happening?
A: Its been some time like 3 months ago, at the begining I thought it was related to a network issue, and after a review from our hardware network expert he didn't found any problem, then I started to think it was related to duplicated IP problems, so we made a review of all IP addresses implemented, didn't found anything, anyway we setup new IP addresses for Remote PC and M22 device, but still the same problem.
2. About how often does this issue happen?
A: There is no a time basis on the frecuency of the issue, some time a couple of hours, some times days, but after the deadlock is present it never came back online until you reset M22 device.
3. Is there any kind of pattern to this issue? For example, does it seem to happen every so many hours, or at a certain time every day, or only when certain software is being run on the host PC?
A: There sin no pattern on frecuency of this issue. The remote PC is running only 1 application, a SCADA software from Citect (www.citect.com) anyway I still can connect and control it using a VNC client in local and other PCs.
The next time this issue happens, please collect the following information BEFORE cutting power:
1. Can you ping the M22 from the host PC?
Yes, I can still ping the device, only running a ping -T it shows a esporadic timeout.
2. Can you log into the M22 webpage from the host PC?
Yes, I can log into the M22 webpage, however the answer is more "slow" but I can't still made modifications, if I can do a reboot from this page, but since this M22 is password protected and operators doen't have web access it was not posible to implement this solution.
One thing that I found recently from this M22 device (we have other) is that some times I used to enable the VNC server to monitor what operators seen on screen, but each time I try to connect to M22 using a VNC client the M22 doesn't allow connection and reboots. This operation works fine on other M22 device.