Best practice Error management

Hi Folks 

I was after some advice  resolving errors.  I have had the following truncation error (*See screenshot). 

I have

1. Identified the type of error by looking at the "output"
2. Redirected the errors
3. Viewed the data causing the errors in a data viewer

However, after viewing the column causing the truncation error, I can't see why it (the sim_state-modified column) is generating a truncation error. The error generating output seems to be the same length as the non-error generating out etc.  Can someone suggest the next logical step?

Regards

Steve