I received a Hardmode Sniper Rifle from the King's Fall raid and wanted to infuse it into my Black Spindle to make my Black Spindle higher. As shown in the imgur link, although I had all of the materails needed to infuse it did not prompt me to infuse the weapon (neither were locked). I held the 'X' button [Xbox One] and it did infuse into my Spindle. I'm not sure if this is an issue with the resolution settings on my ASUS Monitor or if it were intentionally making the text too long to include the 'Hold X to infuse' bar.