Issue Details
I am designing a LabVIEW code for my application and found that when Diagram Disable Structure is used, even without wire connection, its output tunnel remains solid colour.
I also observed that when the VI with this issue is saved, when it is opened, the following error will prompt:

LabVIEW: (Hex Ox1) An input parameter is invalid. For example if the input is a path, the path might contain a character not allowed by the OS such as ? or @.
An error occurred loading VI 'bug.vi'.
LabVIEW load error code 3: Could not load front panel.
Is this an expected behaviour? Below is an example of my block diagram:

