After winning the T4 Julra , I put my stuff in Eternity cache, then I press the button and nothing happens.
You need to change “era” to see the outcome of a slam at the end 
Yes, i know i must change era)) but there is empty cache in the ruined era.
After i click “seal cache” window closes and that is the end))
I am currently experiencing this same issue. I crafted 1H Axe with the stats I needed then duplicated it with rune of creation so I could have two try’s on getting what I wanted. The original axe works just fine and slammed. However, when I try using the duplicated axe, I hit seal and nothing happens. I swap era and the seal is empty nothing there. When i go back my items are still in the cache as if I never hit seal.
edit: I used the cache to try a different unique with a different exalt and it slammed just fine. It must have something to do with the duplicate axe that will not allow it to slam. Originally I thought since I only chose T2 maybe that was blocking it since the exalted was req. lvl 59 and the unique was req lvl 27, but still even after clearing a T3 and trying again same result. Still unslammable.