Is it normal at 4weeks flowering to have one or two bottom leaves start to yellow?....literally just one on one plant 2 on the other....everything else is in tip top shape...just those couple bottom leaves fading out.
it can be for many but if you keep giving them veg food this will stop
i feed veg food right till the end, no flower food no boosters just veg food thats it, ask your self this did you get any of these problems when you was in veg ?