avg_fragmentation_in_percent remains high although Rebuild Index task is complete

Hello, 

Reading through online and forums I've seen recommendation if avg_fragmentation_in_percent goes above 40% Rebuild Index. 

I've now completed Rebuilding Index, however the avg_fragmentation_in_percentage remains as high as above 90% for lots of table. 

Is this normal, could you advise?

Best regards, 

Mohan