In pre-12.9 releases of SDM when the length of the Description field exceeded the 4000 character maximum the system allowed the individual to paste in more than this limit and presented an error message indicating that the length was too long and the total number of characters. Now the system truncates the message when the paste occurs and does no notification that it did so.
If the person creating the ticket is not observant the ticket will not have the information. If their standard workflow is to delete the email then relevant information is then of course irretrievable.
This same issue occurs with the Manual Notify screen. If the character limit is reached and a Manual Notify is attempted the person just can't type in the box. No message, it just behaves like it is broken.