Improved Covert Research Facility in C4 Shattered?

Question for the player base - don’t know if this is a bug or not but today I came across an “Improved” covert research facility in a c4 shattered.

I know that shattered systems are supposed to be able offer sites that are 1 level below or above (i.e. C3 or C5) but didn’t realise this included an improved ghost site

I though only Superior ghost sites appeared in wormholes

Has anyone else come across this or do you think it is a bug that is worth reporting??

Sounds like you were in a Sansha system. Those spawn Sansha-specific null sites, including Improved Covert, DED sites, and even Superior Sleeper Caches.