I believe bots are unable to reproduce despite storing something in .repro when they are in certain locations close to shapes. In any case, I'm getting vegs (Alga Minimalis) trying to repro but failing when they are located close below the only shape in my sim, though there seem to be no reason why repro should fail and while vegs located elsewhere repro correctly.
To reproduce the bug with the sim attached, pull a newly spawned veg just below the shape, it'll quickly reach 6000 nrg and start spinning, which indicates its repro gene is activated.