Hi: There not an expert but that looks like a the start of a male flower to me
Watch it like a hawk for the next few days and it U dont want a male plant get it out of ur grow area pronto it WILL pollinate the rest of ur plants
Could be new growth at the very top of the plant in pic 4, but im leaning towards male private parts. Investigate that very top node and see if you have a couple sacs piling up.