If you have problems with the tags, and you can’t write/read the values of the tags, try this. It probably helps you.
NOTE THIS IS FOR IGNITION 7.7 DON’T KNOW IF THE NEWER VERSIONS HAVE THIS…
In the OPC-COM server configuration, there’s an OPC Setting called “Use Async Operations”. I unchecked this setting and after that, I can read/write the tags without any problem.