Automatic cc-recipient was not configured but it was used

[derpman]

Hello,

i use kopano (core 8.7.1.0-1 / webapp 3.5.14.2539-2) on ucs (4.4-8 / 1020).
When I send a mail to certain recipients, a cc recipient is automatically added, although no default CC is entered under Mail in the webapp settings. is there still a config file somewhere in which this entry can be found?

THX