Checkbox selections disappearing

We have a sporadic issue that has cropped up since going live on 9.1. Our AP department, while using Receipt and Order Match in P4314 are loosing their checkbox selections. The may have several lines to check within the grid, so they go through and verify each line that should be selected, and at seemingly completely random points, they will check the next one, and all of the previous selections disappear.

You can recreate this by checking a few boxes, then double clicking one, the rest will become unchecked. However, they aren't double clicking.

They use IE on their local desktops. I had them use Chrome on their local PC, and IE on our Citrix desktop. It happens for them in all three places.
User 1 and 2 have it happen pretty much daily.
User 3 was having it happen so badly, she just gave up multi select, processing one line at a time. I had her change her grid format, and even though she's changed it back, it's better. It's only happening once or twice a day.
User 4 doesn't have it happen at all (though I don't think he spends as much time doing it.)

It doesn't happen under my logon. I even tried to copy their grids to my profile and still can't get it to happen for me.

I thought about opening a ticket with Oracle, but I can't recreate the issue on demand for them… So I don't know if that will help.

Does anyone have any ideas, cause I'm about out?

maybe a silly question from me, but it must be: Did you see it by yourself? The only explanation i have is that the user did not hit exactly the column with the checkbox. if the user is missing the checkbox-column and clicks the attachment-column (the 2nd), the other lines will be deselected

in any case a workaround can maybe help a little: are the lines among each other? if they are, you can klick from -> to line by holding the shift-key during the "to-"-klicking. (or all lines with the checkboy in the upper left of the grid). after that, you can deselect single rows by holding the ctrl-key. if they are not among each other, maybe you can change the sorting of the grid.