I'm growing to hate "space bark"....
In my opinion, once we "confirm" something in the Codex manually, our sensors should be tuned to recognize those things from orbit. If my probes returned "Bark Mounds" instead of "Biological" (reserving the latter for undiscovered things), the game of "finding new life" would be much more enjoyable.
I like this idea. Though personally I'd be just as happy with a type count.... As in there are 2 different biology signals here... So you can choose to go visit sites until you find both.
At the risk of creating "grind", perhaps the space scan can get more accurate over samples, so after 10 or 50 composition scand of bark mounds, they're recognised by by the probes scan.
There's probably room for more gameplay too. Perhaps let us zoom into the surface scan and interpret more weird and wonderful representative audio and visual clues that will inform us of the types. So from the FSS you may be able to determine that there's brain trees out there, or magma spouts or whatever. Or just fly there and probe.
Fwiw..... I've found 2 different types of things quite a bit. Two different spikey things in a notable stellar phenomenon, two (I think 3 once) different geological things on a body and two different biology on planet (when i found brain trees (only once) there was also bark mounds in another location.
There's also plenty with only one type.
I was picking the sites at random. More recently I started visiting 1, 2 and 3 in order and seem to find two different types more frequently......pure chance, or something to do with the weird numbering scatter, I don't know.