The flashing issue observed when using the "Quick Reply" feature in the Google Messages app on the POCO C71 is a known problem associated with the stock Android system design. It is not caused by a fault with the device itself.
For your reference, here are more details of the issue:
1. To temporarily resolve this issue, it is recommended to turn off the system animations through the settings menu, which effectively prevents the flashing from occurring;
2. Additionally, you are advised to stay alert for upcoming software version updates. Once a new update becomes available, it is strongly recommended to upgrade the device promptly, as future versions are expected to address and fix this problem more permanently.