What's there to talk about? Guts saw Femto (and the rest of the God Hand) for the first time since the Eclipse, tried to kill him, and failed. Don't see why this is worth dwelling on for a guy so intensely task-oriented as Guts, and he's not the type to talk about it to other people.
It has been indirectly referenced, though. Puck recalls seeing the God Hand (and visualizes them in chibi form) in Volume 15, and he wonders what they did to make Guts as hateful as he is.