How to fix "IllegalArgumentException: Comparison method violates its general contract!" when indexing a Gems Repository

AuthorFullName__c
Loren Yeung
articleNumber
000004140
ft:sourceType
Salesforce
FirstPublishedDate
2019-06-10T11:17:59Z
lastModifiedDate
2023-01-22T11:06:11Z
VersionNumber
4