This late in the challenges the preview is no longer representing what would have happened, the M1 and M3 Phagocyte is assumed to have constant energy input in a food-rich environment which it isn't the case here.
Your M5 split at 2.41 mass in half (split ratio 0.5), and generate an egg M1 Phagocyte cell with a mass half of that at 1.21 (normally a bit higher but not much), and the egg split immediately again in half to M2 and M3 with about 0.6 mass each. This tiny M2-M3 hatchling most likely would die very quickly since you set M2 with max Nutrient Priority, and M2 flagellocyte will take the mass/energy from M3 to burn when it swims. When a cell (M3) drops below 0.5 mass, it will just vanish, and since the environment is very sparse with food particles and have existing organisms constantly consuming food, the chance is very slim for the hatchling to reach a food particle in such short swim distance before its M3 dies.
To fix it, you can increase the M5 split mass and its split ratio to favor M1, so the new egg will have a heavier starting mass. Also, drop the swim force and M2 flagellocyte nutrient priority and the M1 egg's split ratio so the hatchling doesn't swim too fast using too much energy, and can travel and survive for much longer. And personally I would change M1 to secrocyte and M3 to glueocyte, so the hatchling can have more attraction as well as have a chance to be attached to other organisms to leech energy, hence its split mass can be set higher and later becomes a much healthier long-lived grown-up. And finally, you can change the M5 's children split angles (and M5's own angle by changing the M3's children 2 split angle), so the hatchlings will spread out more evenly in all directions.
This is the modification applying the above suggestions and with the right starting location close to enough preys near the center of the dish, it will pass this level.
https://www.dropbox.com/s/7jvfnu4khg2hq ... enome?dl=0