There was a ( backdated ) ATP 04/08/25 rankings update last year including the Toronto Masters so ATP points are due to drop off.
I recall it all being rather confusing last year with the first year of the Canada and Cincinnati Masters covering a 3 week period. Ultimately the ATP backdated and then had no 11/08 rankings update whilst the WTA had no 04/08 rankings update.
See what happens this year. The North American calendar has shifted back a week for Canada, Cincinnati and the US Open.
Yes all a bit confusing. This point in calendar last year was week one of Canada so no points dropping off .
Toronto finished on the Thursday 07/08 and as I was saying the ATP then produced backdated rankings for 04/08. Toronto Masters points are thus due to drop on 03/08 this year, as for instance are Jan Choinski's German Challenger points for this week last year.
