Did he find it insulting that he had to trial or that he received the offer of trial by email?
My vague memory (it's a while ago now), is that yes that the only communication was via email.
I mean if true (and like all rumours it may not be), it is a very odd way to extend a trial invite. Surely you can spend 5 mins to make a phone call.
What I think is definitely true is it was yes in a time of a head coaching vaccum, and the Nix being fairly disorganised. Post Kalezic was definitely such a time, with Rudan only appointed weeks before the 2018/19 season kicked off.