\uD83E\uDD14 Problem
When trying to export a project, it fails with StackOverflowError. The reason is that the thread is stuck in an infinite loop while trying to resolve circular child groups. Nested groups are possible when using Crowd. There is a way to create circular references, e.g. 'group1' is a member of 'group2', 'group2' is a member of 'group3', and 'group3' is in turn a member of 'group1'.
\uD83C\uDF31 Solution
Identify and fix the circular group references in Crowd.
\uD83D\uDCCE Related articles
https://confluence.atlassian.com/crowd050/nested-groups-in-crowd-1130369661.html