We do testing of the core gameplay for each update to ensure something like this doesn’t happen. We also opened the beta earlier than usual and asked the beta testers to pay particular attention to the core gameplay on the gemboard, no one picked it up either from external, internal QA or the beta test.
We do our best prior to releasing updates but having an update live with a large number of active players does tend to make issues more noticable just due to the number of users.