I'm trying to wrap my head around this one, but in the Stresses Extended Report, isn't the Bending Stress essentially the same term in the longitudinal stress equation? (not sue if SIF is included in Bending Stress, but if it isn't that would just make the difference greater...). Does it make sense that the Bending stress reported can be higher than the Code stress?

Sustained Case Example:

Node 4508
Bending Stress: 22369.8 kPa
Code Stress: 20974.2 kPa
SIFi: 1.157
SIFo = 1

I noticed this more in an Occasional Case that was built off of the above SUS case, although chalked it up to maybe it being a quirk in the way the cases are combined (which is why I went back and looked at the root SUS case)

Occasional Case (above SUS + Seismic)

Node 4508
Bending Stress: 194998.7 kPa
Code Stress: 148599.7 kPa
SIFi: 1.157
SIFo = 1

Any thoughts would be much appreciated. A bit embarrassed to be stumped over something simple like this but here I am

Which code are you using?

And how's the the line temperature and pressure?

And if you adjusted any of 'SIFs and Stresses' at configuration editor, please let us know.

Code stress less than bending stress is weird, I guess....
since code stress comes from resultant value of stresses such as bending + torsion + axial(b31.1 not) etc.

Sorry, should've included that: B31.3.

Caesar is current version, (8.00.00.56000) default settings (except for units).

Double checked and reset to default settings and values are the same (with default settings output in psi).

Those extra stress columns in the CAESAR II stress reports (e.g., bending stress) are general stresses. They are not related to specific Piping Code formulations.
Those columns continue to use the SIF as the moment multiplier rather than the (current) SSI.

Try this to confirm...
Reset the stress category to EXP. Except for additional axial load and shear by torsion, I expect your "Bending Stress" column to match your "Code Stress" column.