Exported tag value doesn't match what gets exported to tags.json

A bit of a head scratcher here in version 8.1.17.

I have a folder of tags and UDTs that I am exporting to tags.json. I can see that a specific tag is set to 240 in the designer tag browser. However, tags.json shows this tag is set to 183.

Periodically, the UDT tag value will update itself to become 183. Even if I change the value back to 240 it will eventually revert to 183.

I created a second UDT by copying the first UDT and renamed the instance of the UDT in this case to myUDTname2 to verify nobody else was writing to this tag and the problem still persists.

My questions are:

  1. Why the discrepancy between what I visually see the tag is set to and what gets exported to tags.json?

  2. How do I fix this problem?

So on the new tag, if you change it to 240 is it also switching back to 183? If so, how is that tag bound? Is it a memory tag? Are there any scripts inside the UDT that could be writing to it?

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The new tag is switching back to 183. The new UDT is given a different name so I am pretty confident no external parties are interacting with it. The tag is a memory tag. There are scripts in the UDT but they do not write to it (as far as I can tell).

What I did find is there is a reference tag inside a second UDT in the folder that references the memory tag in question.

If I disable the override on the value source I see the following:

So I am wondering if Ignition is getting confused on all these overrides.

What is interesting is I have several of these machines setup the same style and they don't have this problem.

After some further investigation it seems that reference tags are bi-directional and once I got rid of the underlying override the export stopped producing a value property.

Problematic tag (I made it readOnly after the problem started)

image

Less problematic tag?

image

So now with the reference tag removed, how are things reacting on your memory tag? Or am I getting things confused now?

So far the 183 has not returned. I think this is a case of Ignition doing something funky with my unexpected double override I had going on plus bidirectional references (which I didn't even know was a thing).