Is there a cap on Kavat genetic codes?
Solution 1:
No, there is no cap to Kavat Genetic Codes, and no standing caps effect whether you get them or not (more specifically, you can still receive them even if your Cephalon Simaris standing is capped). I personally have received genetic codes when capped in all forms of daily standing. Daily standing doesn't effect loot drops.
So here is a little math to help you understand what you are seeing. Each wild Kavat has a 15% chance of giving you Kavat genetic codes after scanning them. This means you have a
(1 - (1-.15)^N) X 100%
chance of getting at least one genetic code for N scans. With 12 scans you would only have a 85.78% chance of getting at least one, or about 14% chance of not receiving one. With 20 scans you have a ~96% chance of getting at least one, and anything past 30 scans falls somewhere between 99-100% chance of getting at least one code. However each scan is independent of another, each scan has an 15% chance of giving you a code regardless of any previous results, so it is completely possible to scan 30+ in a row without getting a single one, though the odds of it happening are fairly low.