Environment:
Firmware Version | 0.2.6
Base Version | 9.0.19.02_202007141512
Model Suffix | y21ga

It looks ftppush.sh detection of already running script fails causing it to duplicate. Caught this while looking for potential reasons for spontaneous reboots.
Example 'ps check':

# ps | grep ftppush.sh | grep /bin/sh
 2020 root       980 S    /bin/sh -c sleep 40; /tmp/sd/yi-hack/script/ftppush.sh cron
18023 root       980 S    /bin/sh -c sleep 40; /tmp/sd/yi-hack/script/ftppush.sh cron
27595 root       980 S    /bin/sh -c sleep 40; /tmp/sd/yi-hack/script/ftppush.sh cron

while looking at the code there should be only one instance running. Debug in progress :)