The wrong window scrolls beside a card game: check inactive window scrolling
If a reference page scrolls while your card game remains selected, look at which window the pointer is hovering over. A wheel movement can be sent to a window without bringing it to the front.
What to check
Windows has an option to scroll inactive windows when hovering over them. Read the setting under Bluetooth & devices > Mouse and check whether the behavior occurs in two ordinary windows. Keep pointer location and the active window separate in your notes.
Compare one example
With the game active, hover over a neighboring help page and turn the wheel once. Then hover over the game and repeat the same movement. If only the hovered window scrolls, inactive window scrolling may explain the observation. If the cursor is over the game both times and its behavior differs, record the affected game screen.