Refreshing the portal forms page constantly while plugin is being updated causes custom field (from plugin) to disappear

Issue Summary

Custom fields (from plugins) configured for the request type may disappear if the request form is constantly refreshed while the plugin is being updated.

The custom field needs to be re-configured on the request type (edit field) page for it to show again.

Environment

Jira 7.13.8 / JIRA Service Desk 3.16.8

Steps to Reproduce

1. Install blank version of JIRA Service Desk 3.16.8.
2. Install CustomFields++ 1.6.4-jira7.
3. Define a Checkbox++ custom field and add to request type.
4. Verify that the field shows up on the request form.
5. Update CustomFields++.
6. While the plugin is being updated, spam refresh on the request form.

Expected Results

We would expect that the field temporarily disappear and re-appear after the plugin has finished updating.

Actual Results

Field permanently disappear. The custom field exists on the Custom Field UI page. However, it's configuration is not visible on the request type's edit field page.

Issue is reproducible on custom fields that are derived from other plugins. Tested with Insight custom field as well.

Workaround

Reconfigure the field on the form.