This detailing, or lack of it is so hard to really put your finger on a solution that fits all windows.
Sometimes it is atmospheric conditions, other times it is a particular type of window, there is the one type of UPVC one that I always found a real pain
This is the one where the window seal seems to be recessed, the glass goes right to the UPVC part of the frame and then under it, and there is a small gap all the way around the glass, or rather between the glass and the frame it goes under.
They seem to have quite deep seated reveals too, which also makes squeegeeing a little more difficult.
You also need to make sure you do not have your applicator to wet, the detergent you use also has a bearing, if you are using good old fairy liquid and have it too 'slimy' then you will find it even harder not to detail. The specialist liquids are best.
If the window are dirty then you have to wash all the edges, top included if you want to do a decent job, but even then you can help to reduce detailing after squeegeeing by detailing BEFORE you squeegee.
Yeah, yeah, I know, you are still wiping the edges, but providing you are not using a scrim or microfibre that is too wet to do this with it can leave you not needing to to 'dry' detail the window, and it is faster because you don't have to be fussy about it.
Different combinations of channel and rubber can make a difference too, 'dog earing' certainly makes a big difference, as does how much of the rubber you leave protruding from the ends of the channel.
It's just my own personal opinion, but I have found (at least for myself) that the Ettore channels (brass) and their soft compound rubbers to be the best, and better still when the channel is an old one with 'rounded' off ends
Another thing to watch out for is a warped/bent/twisted channel, though perhaps that doesn't have a great effect on reducing detailing, though it will affect your squeegeeing.
Sometimes, if you wish to do a top job then you have to detail at times.
As the saying goes; The devil is in the detail
)
Ian