Answer card doesn't revert to "?", previous answer remains

Hi. Thanks for the superb app, loving it as always.

However. in pracitce, for the last couple of days I have target-language-word A on the left and “?” on the right. I click the “?” and answer A comes up as usual. Then I click the left card for a new target-language-word-B on the left and on the right instead of “?” I still have answer A sitting there. This happens on different browsers, after logging in and after closing and opening the browser.