This warning has been raised because the index is fragmented more than the percentage limit set in the Aireforge Studio settings. Highly fragmented indexes are less efficient and can use more storage (disk and memory) than less fragmented ones.
Depending on the level of fragmentation, Aireforge Studio may recommend either reorganizing the index or completely rebuilding it.
Implement an index maintenance job.
Any suggestion from Aireforge should be thoroughly tested before being implemented into production.
Reorganize and Rebuild Indexes | Microsoft Docs
DBCC INDEXDEFRAG | Microsoft Docs
SQL Server Index and Statistics Maintenance | Ola Hallengren