All this "muh, you need to explore", and "L2 plant preferred habitat" is missing the point. The Heat Map lies to you. There are examples of planets where the ENTIRE thing is both covered in blue, for say bacteria, but it also us covered in a rough/spiky terrain. You can 'explore' (read wander aimlessly looking at the same 4 shades of brown) for hours and never see a single colony because of the mismatch. It's unreliable and arguably useless in way too many situations. This post shows the problem in better detail.
Nope, doesn't happen, I have always found bacteria where indicated on the heat map, sure sometimes I can't land because the ground is to rough and I have to fly on to find flatter terrain, but it's always there, there is no mismatch, if it's blue, it's there!