The confusion over the portfolio of Stife between Bane and Cyric started with the 3e FRCS which did falsely list strife among Bane's portfolios and not among Cyrics. While this error was corrected with the FRCS Errata (page 3) the error made it partly into Faiths&Pantheons (which contains the error at pages 14 and 20 but also got it right at page 223).
About the issue with F&P the following has been posted by Sean K. Reynolds at the WotC message boards at May 11, 2002 10:55 AM:
I think I figured it out. Here's the sequence.The designer for Bane must have used the pre-errata version (understandable, as the errata didn't come out until after this book was designed). [...] So no, Bane does not have strife as part of his portfolio, Cyric does.