It could be that the Chinese and Russians have been focusing their efforts on detecting the F-22 and/or F-35 and here we bring back the one stealth aircraft they have no experience with and thought we got rid of.
The F-117 looks stealthy-er like the B-2 than the F-22 or 35.
As I recall, these aircraft were very hard to detect with modern radars but they showed up like a sore thumb on some older Soviet systems - different bands used.
It looks that way because of the limited computer power we had designing it back in the 1970s.
I would imagine however they improved some of the coatings on it, and the electronic systems are probably upgraded now.