Text custom fields filled with a single letter A aren't searchable

Issue Summary

Jira search doesn't work on a text field whose value is a single letter A.

Steps to Reproduce

1. Create a single line text field and add it to screens
2. Create an issue and type just the letter A in the field
3. Create an issue and type just the letter B in the field
4. Search for issues: "custom field" ~ B
5. Search for issues: "custom field" ~ A

Expected Results

Jira would bring the issue when searched for ~ A as it does with ~ B.

Actual Results

Results are empty when searched for A but it works when searched for B.

Workaround

Use phrase search: "custom field" ~ "\"A\"".
The search remains case insensitive.

Further information available in the KB article Searching for single words in text fields does not work in Jira.