Can comfirm this behavior - also in the nightly release (mtn checkout) - texts created by

SOGoAptMailICalReply.m

that belongs to "bodyFormat" are not translated (in my case to german)

what i did to solve it for me, was to transform the line 116 from:

bodyFormat = @"%{Attendee} %{SentByText}has accepted your event invitation.";

to:

bodyFormat = [self labelForKey: @"%{Attendee} %{SentByText}has accepted your event invitation." inContext: context];

that worked for me - don't ask me if it's correct, i'm not a developer in this language..

Fixed bug see https://github.com/inverse-inc/sogo/commit/26c97fe4ed7b652498b3b4d9246ed664f88d8bd8