Not all emails processed by mail handler

Steps to reproduce

1. Install Service Desk 2 (my version is 2.0.2)
2. Configure mail handler through
   Service Desk > Settigns > Email settings > Turn it on
3. Once successfully created, send multiple emails one after another immediately
   • In my testing, I sent 4-6 emails immediately after each other

Expected Results

• All emails created as request in Service Desk

Actual Results

• Some emails will be left un-read in the mailbox
• Not created as request

Notes

• Not able to consistently reproduce
• Seems to be easier to reproduce when the inbox have more mails
• Tested with Gmail