Use locking in the app to prevent concurrent address-list insertion within the process.
When current MikroTik address-list is being updated and when new decision comes in,
then there was a possibility that command to add address to address list happened
after connection to the MikroTik was closed.
Adding simple mutex lock should prevent this.
If you use concurrent bouncers then this still may happen anyway, as there is no shared
state among the multiple instances of this app.