The challenge “Gather Berries” doesn’t progress, regardless of how many berry bushes you harvest, the type of berry bush, using tools… I’ve tested in private games as well. It is an impossible to complete challenge. I’ve checked with multiple other people and they all agree this challenge doesn’t work. We’ve tried on private games, our PVE server, restarted the server… whenever this challenge comes up, we know we have to reroll if we want to complete all 5 of the XP bonus challenges.
Are you, by any chance, using mods? I was able to complete that challenge several times in single-player and on official servers.
Also, are you harvesting the whole bush? It’s not enough to just grab some berries from a bush, you have to do it until the whole bush is gone.
You also have to actually get berries from the bush in addition to destroying the bush. I noticed that the highlands berry bushes don’t always hand out berries, and when they don’t then you don’t get credit for the achievement.
I’ve tried with and without mods, to no avail. And I’ve harvested multiple bushes, enough to get several stacks of berries, but it never actually processes through the challenge.