_Time_System does not appear to update correctly in tests on Matrikon OPC

- no error messages are returned from OPC
- value will "sometimes" change
- could this be because the OPC-server detects the change as small?

Start by reproducing the acceptance test with the Matrikon OPC server and observe updates to _Time_System. Compare cases where the value changes with cases where it does not, checking whether the server treats small changes differently. Done means the update behavior is understood and the issue has a reproducible result or a confirmed fix.

Written by the indexing model from the issue text.