Stacking cloth of the same color and type does not work anymore. The same issue is happening to scraps making it impossible to craft anything that takes more than one piece of either.
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I've tested this and can confirm it does exist. Furthermore, when the items are traded they stack. I split the stacks after trading and was unable to stack them again.
You are able to combine stacks again if you split a stack in your inventory (and select the entire stack) and place it onto another stack. This bypasses the bug and works both within the inventory and bins.
Obviously, this will not combine stacks of 1 item as you cannot split them.