guile: I liked F18 too, because i assumed that after G18 the follow up is the exchange E18G17, an empty triangle and J17 is misplaced. It seems that this bad trade is too obvious and not mandatory. The G18 stone would simply be treated lightly for now as sabaki is still possible. Because of this possible tenuki E18 is standard. The follow up is the jump at G18, a much stronger attack that remains open, which makes sense. Maybe a high dan can can shed light on this ?
Resolved.