The two images from 2012 (March and April) are the same event, so no surprise they’d be in the same place.
The third pic from 1997 has this caption:
“A curious plume-like feature was observed on Mars on 17 May 1997 by the Hubble Space Telescope. It is similar to the features detected by amateur astronomers in 2012, although appeared in a different location.”
Ah, I see what you are saying. They were talking about the May 1997 event right above that photo, but it is actually just another one of the 2012 event. My mistake.