It is not normal, and it means that your UDT is not writing some of the data into the database.
This looks like the same error that I am getting.
UDT doesn't surface critical errors anywhere you can see them, it's only when it stops writing the data into the database and only when starts to look funky do you begin to look in the logs.
Open a support case; you might want to reference case#588173
[I am somewhat glad this is not only me, and as an aside there are two bugs here:
a) the UDT business layer is not re-establishing the database connections when they get broken leading to a thread that will never work.
b) there are deadlocks in the SQLserver stored procedures that case database connections to be broken when the deadlock protection selects a process to be killed
]
If you restart the ModuleEngine then it'll begin processing UDT tasks again until the deadlock kills a thread...