Works for me. The only explanation I have is that you have "linked" the two layers(*). When layers (and other objects) have "links" (link icon right next to the view icon in the list), then transforms applied to one object are also applied to the other linked objects.
The fix is to click on these links icons to remove them.
(*) How could this happen by mistake? Simple: if a layer has a link and you duplicate it, the copy also has the link. So you could have linked the first layer by mistake (when only one layer is linked, nothing changes so it goes unnoticed) and the link stuck wen you duplicated it.
(*) How could this happen by mistake? Simple: if a layer has a link and you duplicate it, the copy also has the link. So you could have linked the first layer by mistake (when only one layer is linked, nothing changes so it goes unnoticed) and the link stuck wen you duplicated it.