Show/hide buttons not working properly

I'm creating an interactive bingo card PDF for a client where the user clicks on the boxes to mark an X and mark five boxes in a row to 'win'. All the boxes are buttons with Xs on top all as buttons, but hidden until triggered. Clicking the box sets the visibility of the X on top to show. The problem is that when the next box is clicked the first X disappears, so only one X can be shown at once. In the visibility properties for the boxes, 'show' is only set for the corresponding X on top - all other buttons are set to 'ignore', but they aren't being ignored and hidden instead - why?

Here is the PDF - https://markharrington.design/wp-content/uploads/2020/05/bingo-card-forum.pdf - will need to be downloaded and opened with Acrobat.

Sometimes after clicking lots of random boxes, some of the X's stay visible for no explicable reason. If it's a problem with the layer order, what's the point of the 'ignore' markers. This is driving me mad, any help would be greatly appreciated!