JIRA /rest/auth/1/session endpoint returns a redundant empty cookie

Summary

Accessing the /rest/auth/1/session in some cases returns 3, rather then the expected 2 cookies. Additionally, the extra cookie has a blank value but no expiration date.
E.g.

studio.crowd.tokenkey=""; Domain=.foo.atlassian.net; Expires=Thu, 01-Jan-1970 00:00:10 GMT; Path=/; Secure; HttpOnly
studio.crowd.tokenkey=REDACTED; Domain=.foo.atlassian.net; Path=/; Secure; HttpOnly
studio.crowd.tokenkey=;Version=1;Secure; HttpOnly

Environment

1000.784.2

Steps to Reproduce

1. Call the session endpoint with curl using the D option to print the header. E.g.
   {{curl D -H "Content-Type: application/json" -c cookie.txt -d ' {"username":"USERNAME", "password":"PASSWORD" }

   ' -X POST https://INSTANCE_URL/rest/auth/1/session}}

Expected Results

2 cookies are returned

Actual Results

3 cookies are returned, and the last one has a blank value and no expiration date:

studio.crowd.tokenkey=""; Domain=.foo.atlassian.net; Expires=Thu, 01-Jan-1970 00:00:10 GMT; Path=/; Secure; HttpOnly
studio.crowd.tokenkey=REDACTED; Domain=.foo.atlassian.net; Path=/; Secure; HttpOnly
studio.crowd.tokenkey=;Version=1;Secure; HttpOnly

Notes

This issue only happens to instances that are using the old authentication system

Workaround

The current workaround is to ignore the blank cookie (it should not be returned at all).