Cathay Pacific will be just 3 weekly for May, before going 5 weekly from June onwards.
No flights on 1/9/16/22/29 May.
No idea what's caused the reduction but at least it's just 1 month. LHR also has lots of dates where it goes from 5 to 4 daily in May, so, looks like it's a system wide issue and not MAN specific.