Composite steel girder designs that were previously passing and designed with studs will sometimes revert to having 0 studs and then fail bending or deflection checks. This can happen when the designs are frozen and the model is "reframed" which happens for most any kind of change to the model. It can also occur when modifying the design for girders that have more than 5 stud segments.
New defect in version 15.02.00.00. Optimized designs with studs still have the right results.
A solution will be released with version 15.03.00.00 soon. If the model was recently converted to version 15.02.00.00 it may be worth reverting to version 15.01.00.00 and restoring the model from the automatic backup file.