Schneider has released a hotfix for 1.9.2 that fixes the issue with the BACnet values going stale on graphics and in the watch window. Other changes are outlined in the attached PDF.
Download 1.9.2.4000 Here:
https://www.dropbox.com/sh/3blbpe071spm5h7/AAC_7IL2-SQcB0hW_gEMHB_na?dl=0
Additionally, other fixes can be done to better the performance of BACnet COV values.
Step 1 - If you don't have an up to date firmware set in Workplace Tech, download that and update the firmware of all controllers. This might be the only step that you are required to take. As of 1/29/18, the up-to-date versions is 01.434 for MNB-70s and MNB-300s and 01.515 for MNB-1000s.
Step 2 - Increase the subscription lifetime of COVs. In Control Panel, click on Interface Manager
Step 3 - In Interface Manager, scroll to the bottom and change the value from 8 hours to 12 hours
Step 4 - After that has completed, go to each device still experiencing the issue and renew COV subscriptions.