Additional SQL Server features and topics not covered by specific categories
Thanks for the information. I don't have a solution right now, but I have some ideas for troubleshooting.
If you are on SQL 2016 or SQL 2017, make sure that you have the more recent Service and Cumulative Update (please share the output of SELECT @@version) and then run
DBCC TRACEON(460, -1)
This will change the error message String or binary would be truncated so that is relates which table and column the error relates to, and you also see the truncated part of the data.
The other recommendation is that you set up a extended-event session which captures the event error_reported. Then you create a view over this event session that gives you information on where the error occurred. You can also run a stored procedure that gives you the full call stack. You find everything you need to know about this in this article on my web site: https://www.sommarskog.se/Short%20Stories/trace-exceptions.html