I can hear cavitation in my skimmer when i put on the robot

I have inspected the skimmer thoroughly there are no cracks or holes. During normal filter operation there are no issues; once i put on the adapter, hose and robot i can hear cavitation in the skimmer and i can also see bubbles in my pump basket through the lid. All my hoses are new and robot is new; same thing happens when i put on my manual vacuum head as well. this cavitation with all the bubbles doesn't seem to allow correct filtering. Any idea's on this ?
the pump is new the filter ball top valve is new; I have inspected all the hoses as well.

Not sure what you are hearing but it's not cavitation [ see https://en.wikipedia.org/wiki/Cavitation ].

It sounds like you have a suction leak which shows up under the increased vacuum that results from installing the suction side cleaner. Unfortunately, suction leaks are often hard to find . . . especially when the equipment is not in front of you. The only tip I can offer is that suction leaks ALWAYS result in openings (intermittent or not) in the piping & fittings between the pool and the suction intake of the pump. That includes the pump lid. Once you add the cleaner, it also includes the cleaner hose and fittings.

Sorry.