After joining a guild when do buffs kick in
When they get refreshed by the guild. They last 1 week, so generally at most, 1 week until they kick in for you.
Edit: the guild does need to be set as your primary guild at the time when they reset them. And if you change primary guilds after that the buffs will drop cancel.
Thank you for the help
In short, Guild buffs are only given to you when the guild is set as your active guild [whatever tag is above your head] and the buffs are being turned on. So if you join in the middle of the week when the guilds buffs are already active, just be patient, 7-days goes fast and when the buffs are reactivated/re-turned on, you will get them.