OPC UA Modbus bad quality tag

Hello i am having a problem,
i just add some tag for my modbus connection.
But quality is BAD,
what is unusual if i use OPC quick client, i can read the tag(see top of screenshot) but not suscribe (see lower par of screenshot).
i have many other tag on this same connection working fine.
but all what i need to add seems not working…
any idea what should i do ?

If you disable the “Span Gaps” advanced setting for that Modbus device in the Ignition Gateway does the subscribe for that tag start working?

Yes it solves the problem.
Thank you for quick answer.