Retainer Venture

[Kyana]

Looks like a bug.
You should provide detailed information for the devs to check this.

EDIT:

• Please be sure to include all of the necessary information when making a bug report. (Date and time, location, name of NPC, action you have used, name of item you have used, steps on how it occurred, etc.)

It shouldn't make any difference if your retainer is selling items or not when you send him/her on a venture.
I didn't come across any problems so far, so it might have something to do with a certain procedure or item which creates the problem.