Refund changed/amended to a weird amount (dollars & cents)

So I did my son's tax return via TurboTax and of course had to mail it in since has to be manually signed by me.  His refund amount was $945.  After waiting more than 4 months for the refund, today they finally deposited $941.94

 

I always thought refunds were in whole amounts & can't figure out why it would be short $3.06.  I haven't received a letter yet but was curious if anyone else ever received cents?  I've been doing my taxes for almost 30 years and this is a first.  I can understand if taxes & penalties are applied when you owe, but a refund?