Jesus told his brothers, "I am not yet going up to this feast" (7:8), and then he went up (7:10). How do the two fit?

Here is what John's Gospel tells, in order. Jesus said, "My time has not yet come, but your time is always ready" (7:6), and "You go up to the feast. I am not yet going up to this feast, because my time is not yet fulfilled" (7:8). "Having said these things to them, he stayed in Galilee" (7:9). "But when his brothers had gone up to the feast, then he also went up, not publicly, but as it were in secret" (7:10). In the WEB he says not yet, and gives a reason with it: "because my time is not yet fulfilled" (7:8). John's Gospel doesn't say more about why he went up when he did, or why in secret, and these notes don't either.