IMEI changed, is something funny going on here?

I sent my i9506 off for repair and the seller (not Samsung) replaced the motherboard under warranty. It all looked good, expect for network drop outs that I am still trying to resolve, but I noticed the IMEI and serial number have changed. OK, they changed the motherboard, so I understand that, but when I put the IMEI into www.imei.info it says the phone is a Wingfone W9300 not a Samsung i9506. Huh? The hardware looks fine, all tests say it is an i9506, antutu performance is great, etc, but is there something fishy with the IMEI that I should know about?