This been here for a while now.
While you hold shift + left click in your inventory to place it in your left hand slot. i’d say that 70% of the time it triggers an auto click on the left hand action. So when you left the inventory it just start using what you have in your left hand.
When you have a high dmg + speed +aoe hammer equipped, it’s pretty devastating in your own builds.
yesss so many accidents happened to me this way
This happens to me a lot too. I’m left handed and keep my hammers etc in my left hand so the results can be frustrating. Probably the worst one is when I’m holding a chisel and effortlessly ruin my walls with swiss cheese holes.
Thank goodness the devs made storage blocks, machines, etc always require multiple hits. I’ve had this happen with a hammer before while exiting my spark generator and got to two iron hammer swings on it before I regained control. Losing all your spark like that would be the worst.
It triggers either hand. For me I have my hammer in my right hand all the time. Then all the sudden my hand is possessed like a demon hell bent on smashing my house down, and a swinging it goes,aaaaeeeee
I’m glad you brought this up. The same thing happens to me occasionally and it is very annoying having to replace destroyed blocks.
yea, and its worse when you have a chisel in your hand, and you just finished a nice piece,then away goes the demon arm, like a crazy eddie with a machine gun that won’t turn off. And if you have your action speed boosted, dear God you can wreak some havoc in seconds.
Happens to me too… some of the results are LOLworthy but this glitch definitely wrecks.
It happens to me also, its due to a lag bug. This is fixed by pressing the button again.
Happens to me too. Yesterday’s episode was the most damaging when I rechiseled my base. I now have to spend cleanse points to respec so I can chisel them to how they were.
Just out of curiosity - do you have forged items in your bag that might have an ‘auto’ something or other on them.
I get the left hand tap also but only on one character. Not played on that particula character for a week or so so forget that it had the weird left hand tap.
I have some god awful forged items in my bag from trialling forging. I had some items that had auto magnet I think it was. Even though they were not physically equipped in my hand, one item [hammer] was in the same stack in the bag as the hammer I was using.
It doesn’t really cause me any troubles as I only have one tool in use in one hand anyway, my left hand is only ever for my torch and so the character randomly taps things with the torch.
Just thought I would mention it in case your forged things have a ‘auto’ defect/quirk type thing on it that might be the cause.
It’s the only thing I can think was doing it
I have mentioned this before somewhere… it happens when i close a menu really fast after clicking something
I haven’t gotten this 100% reproduceable because there’s a bit of timing to it, but I do have a lead on this.
It’s not related to menus as I am able to do this with alt+tabbing too.
I believe it has to do with taking context away from the game while you are mid-tool use.
edit: it may simply be doable by holding down the tool use button before exiting a menu.
Your other hand will now be auto attacking like a possessed fiend.
I have a very confusing mouse button setup on account of being left handed and using a left handed mouse. But others have reported this enough that I’m confident it’s not related to my button setup. Still, if someone could reproduce using those steps it would help to verify the problem.
My bug finders fee is the 33 durability I’ve lost on my light source + auto harvest chisel while testing this 
I tried this and I’m not seeing this. I would love to fix this bug but I don’t have a guaranteed way to make it happen. Without a (>5%) reproducible fixing it could be very difficult.
I believe this happens to me often from shift-clicking equipment into my hotbar and pushing Esc very soon afterward
@dave I do have this 100% reproduceable so we simply have to figure out what is different about my setup compared to yours. Here is a gif
https://i.imgur.com/cs0T7g9.gifv
What I’ve done in that gif is:
Despite holding down the left button, I am now swinging my totem (bound to my right button) without any input. If I release the left mouse button the totem will continue to swing, until I click my right mouse button.
The first two steps aren’t necessary, I just wanted to demonstrate each tool working normally as a baseline. All I have to do to reproduce is enter the menu, hold down the button, then exit the menu
can you pm me your controls? Should be in a folder something like this:
I don’t know what RANDOM_NUMBER is (something to do with steam) so you will have to try them until you see a folder called “324510”
C:\Program Files (x86)\Steam\userdata\RANDOM_NUMBER\324510\local\user_settings\default\controls.json
@a13o would be awesome if you could work with dave here to get this fixed. I’d love you forever.
Don’t know if what I have happens fits into this, but will be using my hammer and stop but it continues to act as if I am holding the button down. It always happens when I have the hammer, but then I have set slots that I keep tools in. Left hand is right top slot is the axe, middle the hammer, left is the fist, middle down on left side is the shovel rest is blank or a random item I am using, such as placing blocks. Right hand first is the slingbow top left, middle is a grapple and the rest can be random items or blank.
I have to move her and scroll to another slot to get it to stop.
yeb this happens to me atlest 3 times during my hunts almost always when i got my auto chisel out the bug is going to be the only reason the thing breaks >.<
Ok I cant reproduce it with your controls either 
I can see you have a yellow highlight underneath your mouse. What software is it that is adding that? I’ll try installing that see if it starts happening.
Are you recording with some piece of software?
What’s your FPS? (perhaps I need a slower/faster FPS to make it happen)
Can you tell me what number you get after “Frame Time:” when (or just after) the bug happens
