OPC-DA Tag Group randomly shows Bad_NotConnected

I have been fighting this issue for some time now. We have 4 gateways and 12 tag providers. Randomly we will have a tag group just stop and give a status of “Bad_NotConnected” on the tags using it. The kicker is, it only causes this on the tags that are using OPC-DA, the OPC-UA tags on the same provider using same tag group are not impacted. I can change the tag group at the UDT level and it will correct this issue or bounce the OPC-DA connections. This is just a band-aid though, as we may lose quite a bit of history until this issue is discovered by flat-lined trends. What would cause the tag groups to just stop? Has anyone else run across this and was able to resolve? It happens randomly, 2 -3 times a week across the 4 gateways.

Current version - 8.1.9