I don't know if there is, as Giancarlo reports, bad blood between Ikeda and Homma.
Although I have no personal knowledge of any bad feelings between those two, there have been a few credible reports
(see post 16 specifically) that they exist. What I know from personal experience, having trained with both of them, is that they are both strong personalities with very different approaches to aikido operating in close proximity. Knowing what I know about aikido politics, where sometimes there are two dojos in the same city that are part of the same organization that are not on good terms with each other, I don't find it at all surprising that would be some issues between these two. I would be more surprised if they were on good terms given how different their personalities are.