Before the most recent update, I was finding planets with biology above level 4 on a regular basis (perhaps every 4 or 5 systems I scanned). I'm way out by myself in systems where no one has set foot, and yet now, after the update, I've gone days of scanning without finding planets with any biology above level 1, if AT ALL. I've found a crap ton of planets, but none with anything to scan.
Changes between now and then is possible (there have been such events), but I would expect a lot more noise about it if that had actually happened recently. (Restricting it to undiscovered systems would mean a complication in procedural generation based system state at a cutoff time, and that's a complication most developers would avoid. Anything else would change already discovered systems.) I'm looking for exobio in Hawking's Gap, and I have not noticed any drastic changes. I'm also heating up an alt-account going from the Bubble to SagA, and the only differences I have noted recently correspond to different star density in the galactic map along that way.
If you had wanted detailed suggestion, I would have expected to see at least two locations mentioned (now and then). And perhaps also if you are looking for some particular type of stars. But without that, it's guessing time.
That main guess is that you have crossed (wholly or partially) some kind of limit between different areas of star generation, as imposed by Stellar Forge, or similar generation mechanism. Sparse and dense areas (such as space between galactic arms, and the centers of those arms) have a very different 'feel'. The brown dwarf belt probably falls in this category,
I have an impression that different boxels in individual sectors may also show appreciable differences in exobio frequency, but that's hearsay as far as I am concerned.
(This idea is based on the general recommendation to stay inside the current boxel if you find rich exobiology -- but someone with boxel experience would have to fill in the gaps.)
