Well I log in and the server is great; I grab a set of 4 grass off of a stack of grass and craft a basket (one of the bins)
At this time lag goes from a very stabile 30something to 2240 (yeah huge)

Now I doubt that what I was doing caused any lag but at this point it is worth checking

Check;
Removing stacks of resource from a stack (grass and it was a stack of 30ish 4 piece stacks)
Crafting Baskets
Baskets entering the game world
dropping gradd sheaf (bins cost 3 out of the 4 stack)

Sometimes the answer is a stupid meaningless thing that stares you in the face
(before this my tribe had no lag at all)

Also another thing I noticed was inviting players to the tribe tended to possibly cause lag
We invited this guy Trivium to our tribe 5 times now and every time we invited him there was a rollback a few mins later

Maybe too many invites going on at the same time?

just throwing things out there