Well, first the Bount episodes that Ichinose appears in are fillers, meaning that what happens in them can't be always taken as being true. So you never know. But second, who is Sajin?
i wouldn't exactly say its not true more like its just not worth mentioning in the manga. the only thing i can see not being or not really fitting into the mangastory is the mod souls. It wouldn't make sense to some ppl. if they just suddenly showed up in the manga and they'd serve no purpose. However stuff like Ichigo having to relearn Bankai to use it in the real world and Ichinose could fit in. Plus Ichinose may not be in the manga but Tousen still is and he demonizes Zaraki for killing the former capt.