I have LassPass version 4.97.0 on macOS 12.4 and use Safari 15.5.
When I select the triple dot icon at the top of Safari for a site that has two accounts (it's a bank with my account and also my wife's account), the fill choice window appears off the screen to the left and is unusable. If I move the Safari window to the right so half of it is off the first monitor, then the fill choice window appears near the left side of the left monitor.
I appears that the program is using the full width of both monitors to compute the distance to separate the fill choice window from the main Safari window. It should rather compute a distance based on the width of the Safari window or the width of the first monitor. At least it should have a reasonable maximum value for the separation distance.