Deficiencies

I can see the things you where talking about. yellow centre not as green as the other. I think this is an issue with the feed and the medium used. 5.8 is good in coir but 6.0 also works. plus if there is any swing in PH in the medium the 6.0 has a bigger buffer before things go south from to low of a PH. all the nutrients you are giving them are readily available and do not need any breaking down by microbes to feed the plants so if they hungry they may need a different ratio then your giving. Plus you can over water anything if its root system is very little. the smaller plant looks to have had wet feet and should bounce back in a bit. typically Iron or sulphur comes to mind when I see that type of coloration on the plant. but your feed should be supplying all that. FYI, your tri part feed should consist of Grow, Bloom, Micro with optional Ca-Mg and Si, another great add on is fluvic/humic acids. I do not see any Grow in your diary being used, is this a typo? Might also be the reason this is happening. and when useing Si, best to mix it in first and let it sit for a bit before adding other things. it can precipitate out and raises the PH a bit. so some PH down will be needed at the end of mixing. lighting, in your diary I see you are doing 24/0, I'm not a big fan of this as all living things need downtime and sleep. plants are no exception. I'd drop your schedule down to 18/6 or even 16/8 if your lights are strong. Gotta find your DLI as that rate is whats used for calculating how much light the plant needs. anything between 35-40 is the upper max they can handle with out additional CO2. Next thing I would look at is your feeding concentration, I don't see a PPM or EC value for the feed going into the pot. It might be to strong or week and causing some of these issues your seeing. If you only using the recommended guides by the brand. go with the lightest option. Autos do not like heavy feeds and they can get stressed about it and go into early flower from it. Maybe even less then the light. EC should be aorund 0.4EC-0.6EC first few weeks then bumping it up to aorund 0.8-1.2EC over the next few weeks, some plant can handel more aorund 1.6EC but hard to tell without trying. This site below is a good guide for auto feeding I like. https://www.thcfarmer.com/threads/med-man-method-ppm-ec-chart.73326/ Lot of potential things I see that could be contributing to this. Try to fix some of the things one at a time to see what works. Good Luck!