Found such a problem.
I use sogo and clients connected via EAS
SOGoAppointmentSendEMailNotifications = YES
Accordingly, sogo should send invitations to meetings when creating them in his calendar.

However, many clients themselves send an invitation letter, and then another sogo. As a result, we get two messages about the event in the calendar.
If you disable this option, then clients using the web client will no longer receive notifications.

Ok, while Outlook sends only one message.
During the disassembly, I found out that in the
SoObjects/Appointments/SOGoCalendarComponent.m file after line 1043
there is a disable for sending repeated notifications from Outlook.
Okay, but there are other clients - DeviceType= iPhone/Android/Outlook and if you do a similar hack, then pushes stop working.

ok, at the moment I did a dirty hack
if ([recipient hasSentBy] && !([[context objectForKey: @"DeviceType"] isEqualToString: @"iPhone"]))

and received that send one mail only from sogo (headers not AppleMail) and pushes (and only when the user selects the status for the first time - in other cases they do not come, which is also strange - in theory, a push should also come when creating a meeting too)

I would like a better solution. As an option - a separate option to enable / disable notifications only for the web interface, but not another clients
thanks