You can’t. You just stop posting to a thread (unlike I do now:)) and it will gradually fade into oblivity. There’s no such thing as a “solved” status for threads, although the moderator has in rare cases used his ability to close a thread for further posting.
Both my Nimbus ISIS hubs came with spacers between the cranks and bearings. The cranks go far enough on to be tight but bottom out on the spacers. Seems to work fine.
I haven’t had any experience with ISIS cranks on anything else, so I just assumed this was normal. The taper on ISIS doesn’t seem as steep as on a square taper, so I thought perhaps they needed the spacer to stop them pushing too far on.
I never had any problem with my bearings slipping on my old hubs though (without spacers). Is it possible the OP’s frame is bent, so the forks are pushing the bearings out slightly? It’s better if the frame forks are slightly narrower than the bearing spacing, so they’re applying a slight inwards force to the bearings, keeping them against the hub.
It appears you already have some spacers (little black rings the fit around the axle), but you want to make sure you have an even amount on each side. because they prevent the bearings from moving around if they keep coming loose.