Hi there,
Last night I was forging, I did a set of 3 diamond hammers, then a set of 3 ruby hammers. I got the ruby hammers ot dmg9 which means they should 1 shot T6 rocks.
They had +550 dmg forge effect.
Since my forger alt is not a miner, I switched to my main and then it’s miner skillset and inspected them, sure enough, slightly more dmg than a dmg8 +20 diamond hammer! Nice!
I switched back to my crafter alt (who forges) and did another set of 3 ruby hammers and got that to dmg9 as well! Very, very nice!
I then inspected the 1st set of ruby ones I did in the forge queue and almost had a heartattack!
The stats changed! It went from +550 forge dmg to +70! I checked the ones I did right before checking, the later set of 3, and they still had +550.
Switched to my main, last set +550, first +70. WTF! I was getting really upset!
I saved the video, has the whole process in it, trimmed it to the last 15 minutes to where you can see what happened and in what order, uploaded it, privately, onto youtube. If a dev wants to have a look, please PM me for a link!
Screenshots:
First set of ruby hammers in the queue:
Inspected it, +550 dmg forge effect, yay!:
Did another set of 3, here’s the queue:
Inpected that one too, also +550dmg! yay me!:
Then, after switching to alt and back, inspected the first set again, WHAT?:
I mean what is this for silliness? I switched to my main, the same thing, it suddenly became a worse forge than it was, then back to my crafter, still the same.
I have video evidence, which I immediately trimmed and uploaded. But because the PS4 suspend the game once you start editting videos I had to log in again completely once back. I wanted to write a scolding thread right away!
Then I got back in, with my main, and checked again, phew, both back to +550! What a relieve!
So I mentioned this to 2 in-game friends and remembered that they should be done, so I go grab them from the output screen of the forge.
Imagine my surprise that the middle set was back to +70 dmg! I was upset, again!
So ran back to my workshop, make some more screenshots and lo and behold the bad set of hammers is back, yet again, to +550 dmg.
They seem to be staying that way now.
But what is this for really, really weird bug? Display error somewhere, sure, but, please fix this! Not good for my health! 
Ok, I stupid! Didn’t notice the day/night thing LOL!
But, why at times do they both show the same damage AT THE SAME TIME OF DAY?