The bongos will more than likely stay off-show until development is either fully or mostly done on the new African forest area the zoo are planning, so it may be a few years before they're seen again.
it’s a shame they’re off show although they are breeding well so I assume the zoo don’t wanna upset the current dynamic.
I did hope they would have been put into the old wild dog enclosure instead of the ubiquitous babarusa. Think this would have been a great area for them (lots of trees and cover) but would have required more substantial work to modify the indoor areas and make new gates to link the outdoor areas. Maybe the zoo didn’t want to make that investment.