Duplicate select options as not available when bulk editing issues

Issue Summary

When bulk editing issues, select options may be duplicated and flagged as "not available".

This is an interface glitch and the "(not available)" options can be ignored.

Steps to Reproduce

1. Create a multi select custom field and add it to all context and all screens (to facilitate testing)
2. Populate some options
3. Reindex Jira
4. Edit an issue and select an option on that field
5. Search for issues like "updated > -10m"
6. Bulk edit the same issue recently changed
7. Notice the new custom field will contain a duplicate option flagged as "not available"

This was reproduced in a fresh Jira installation and with Chrome, Firefox and Safari.

Expected Results

The select field would select the appropriate option

Actual Results

The selected options are duplicated and shown as not available.

To trigger the issue for the first time it requires that only issues with selected values are present in the bulk change scope. After that, the options seem to be cached and appear even if the issue selection is expanded.

The source code shows the same option id (10100) though a different option tag:

<select class="select cf-select" id="customfield_10300" multiple="multiple" name="customfield_10300" size="5" data-remove-null-options="true" data-submit-input-val="true" data-input-text="">
  <option value="-1" selected="selected">None</option>
  <option value="10100">A</option>
  <option value="10101">B</option>
  <option value="10102">C</option>
  <option selected="selected" value="10100">A (not available)</option>
</select>

Workaround

No current workaround is known.
The duplicate options can be ignored as it's an interface glitch — the data is correctly stored in the database and index.