Restating that the upcoming novel “Brotherhood” will present a canon version of the Cato Nemodia incident. However, since Labyrinth of Evil has now been edited to fit into canon, you can choose which Cato Nemodia incident Obi Wan is referring to in ROTS. There is no reason why Obi Wan and Anakin can’t visit Cato Nemodia twice during the Clone Wars. Depending on how much that novel conflicts with Labyrinth and if they can even coexist, I may make another update of LOE to reconcile the two.
Sounds like this won’t be too much of a concern. Here’s what the author of Brotherhood had to say on the subject:
I did read Labyrinth of Evil a long time ago (I believe before ROTS released), but not recently so the details are fuzzy. As that book takes place right before ROTS and mine is right after AOTC, they can happily coexist until someone deems otherwise.