I've reported this as a bug already, but I was wondering if anyone has any tips.
I use a Sigil of Luck when trying to farm around. When the going gets tough, I'd like to switch to a Sigil of Corruption. Unfortunately, it seems like once I already have a counter for Luck and switch weapons to the Sigil of Corruption..... I continue to gain Luck counters. If I main-hand the Sigil of Luck weapon and off-hand the Corruption weapon - I gain only corruption counters.
The only way I know to fix this is to get knocked down or to fast travel - neither one is ideal.
Also, if any engineers are reading this, be aware that Kit/Turrent/Golem kills do not count toward sigils unless you get the last hit with the sigil weapon. :\