Hi,
How do these 2 tickets were "sent out" ?
What "send out" means ?
Please provide concrete details about orders, serials, configuration and elements which can illustrate and explain the issue.
With the current information you gave us, we are not able to understand anything, we can't provide any help or explain you how it could happen if we do not know at the base, what is happening.
One thing I can say for sure is that if it was running fine during one year, something you changed in your website caused the issue.
HikaSerial do not generate serials on his own or without any context ; an order has to be created and confirmed so HikaSerial can then do his job.
Regards,