This error messages seems odd, I've tried searching for it but I couldn't find anything useful on it. However, may I ask what JIRA version are you using?
At the mean time, can you try to perform Integrity Checking for your JIRA instance? Becasue from the error message it shows that you have duplicated enteries for the same field. After performing the integrity checking, fix any errors appearing.
If the problem still persists, try to perform indexing, as it may be causing the problem as well.
I hope that helps. :)
Refer to this doc:
There's a similar behaviour explained here:
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