Apprantly I'm not alone. I too have abyssal luck with all the bosses. I've been bossing continously on my Duelist, Thief Master and Wizard to bypass the wait time in between Soki and Queen's Trials and have yet to get anything good from them.
Queen and Soki seem to enjoy giving me galder coupons
I feel glad that people are actually getting uniques though. It gives me the motivation to continue bossing even although i haven't gotten anything/ had Soki banish me countless times while using Tetra/ Casting magic skills.
P/S: I've tried bossing with 60% Drop fortune, but for some reason, it only makes the bosses more prone to giving me galder coupons than anything.