I know how to click "Cencal" button on worker UI, but because of the recent patch, it became quite serious issue at least to me.

My worker is making "Calpehon Timber Crate" at Grana and has a timber packing skill. Now it has over 50% EXP at Level 30 so I would like to reoll its skill, but if I click cancel button, I will have to waste all my material for the worker's current task due to recent patch.

So likle

 before the patch

1) click cancel

2) wait until the worker finishes

3) reroll

 now after the patch

1) click cancel

2) immedately stop, but all the materials will be gone.

3) reroll

Workers at gathering node is fine with this patch, but workers crafting something will lose all its material when you cancel the work and seems like there is no way to avoid this lose. But I do not think this is what PA patchs (if so, they are just...pew) .

Is there any way to cancel your worker's crafting task while not wasting your material?

Fill the responding city's storage, new work won't start if the storage is full.  Putting 25 green accessories for example in all the open 25 spots will make it so that you won't auto start a new set.

In the case of Timber production, take just 1 of your materials needed for crafting that crate out of the storage and a new set will not start.

just take out one of the materials completely and the work will stop automatically. why the hell would someone suggest to just fill up the storage is so a roundabout way to solve this issue.

If you want to cancel a task of a non crafting task, say you are gathering wheat from a node.  

You can also wait for the worker to run out of stamina and stop by itself. Might be annoying to refill other workers manually instead of using the recover all buton though.

I personally never reroll unless all my workers are at 100% and I usually try to time it with someday ive been away from the game for a day+ so that most workers have alredy run out of stamina.

This is where the change is good, as you don't loose anything and get the worker back right away.  Surpose the best idea would to have an option for it to stop now or finish task.

I actually said, in another thread that if you have to chose between instant cancel or stop when task finished, i'll take instant cancel altho I would prefer to have both.

Putting BSP in the CM and/or Inventory is the quickest way btw.

Yeah, but that would actually require competent devs to keep both in.