Issue Summary

Jira 9.9 introduced a dark feature that enables a more modern UI for custom field contexts and options, particularly beneficial when a custom field has more than 25 contexts configured.

It seems when a custom field context contains a large number of options ( 1000+ ) it can cause the custom field options/context not to load properly, resulting in the options and configuration section to be blank.

Steps to Reproduce

1. Create a multi-select custom field with more than 25 contexts ( for pagination )
2. Create 1,000 options for a few contexts
3. Constrain network bandwidth in some manner ( Toxicproxy, etc ) to simulate a larger amount of data transfer ( or simply create more contexts with 1,000+ options )

Expected Results

The admin section will always load the contexts and custom field options correctly:

Actual Results

Contexts and options won't load and the relating page elements appear blank:

Workaround

Remove jira.customfields.configure.modern.ui from Jira's dark features when needing to modify large custom field contexts

Notes
In case you're wondering about the use case here, it's possible to override the custom field selection UI to resemble labels: How to enable Autocomplete Renderer for Multi-Select Custom Field in Jira