She is Russian, Eastern Orthodox or lives in Central or Eastern Europe is the logical answer. Very common in Vienna and other locales around here
Here a few other ideas:
One cannot discount she has Dyslexia of the fingers/hands and has trouble distinguishing left from right.
On the Right
In many Northern and Eastern European countries, including Denmark, Norway, Russia, Poland, and Bulgaria, it is more common to wear the wedding ring on the fourth finger of the right hand. In Portugal, Spain, and Greece, the right hand is also customary.
Instead of wearing wedding bands on their left hands, gay and lesbian couples often choose to wear rings on their right hands instead. Within gay and lesbian communities, the right-handed ring is an instantly recognizable marker of a monogamous relationship, and even marriage within the states that have legalized it.
Now she does have a ring, she has captured her prey. Consequently she is happy with a successful hunt, she does not cares which hand the ring is on.