Two 5n2s Showing New Drive As SSD, But They Aren't

I have a 6 month old and a 2 week old Drobo 5n2 with 5 6TB WD Red drives installed. I just added 2 new WD Red Drives (Model: WD60EFAX-68S) and for some reason the 5n2s are showing a little tag next to the new drives in the Dashboard that says SSD on it. These drives are not SSDs. All the other drives in the units (Model: WD60EFRX-68M or L) are not showing as SSD.
What is the reason for this SSD tag?