CDX shows "hdcd" with CDR's !?

About 30 minutes a weird thing (imho) happened.
I wanted to listen to some music. (no,no that's not the weird part )
So, I got me a CD out my collection and I put it into my CDX. Pressed play and guess what.....

For about 3 seconds the display showed "HDCD".

Now, this may not seem very weird,but... it was a copied CDR. (burned on my computer)

Even more strange is that the original CD from which this CDR copy was made,wasn't a HDCD either! (as far as my memory goes)

but even if I was wrong,and the original CD was a hdcd, I always thought that,when burning a HDCD on a (computer) CDR,the copy becomes a normal non-hdcd CD.

How is this possible ?
Had anyone ever experienced this with his CDX ?

Regards,
Alco