Opera automatically scrolls to a specific location on the page when you move the mouse. Bug or feature?

Question

Opera

There is a web interface of a certain Internet bank. Opera 12.16.
I observe the following situation: if a long table is shown on the screen (so that there is a scrollbar), then when the mouse cursor moves over this table, automatic scrolling always occurs to some specific place in the table. It was not possible to establish a pattern - scrolling can be both to the first line, and to some in the middle. Very annoying!
IE 11 shows the same page without such "gags".
The interface seems to be without js, but I'm not special in web technologies - I can't claim it.
Prompt - where to dig? What to look for in html code and where to check? Is there any way to disable this locally? Is it possible to install unequivocally - a bug of the web interface or Opera?
Z.Y. "Change browser" does not offer.