Not all apps show crossposts yet, or don't do so prominently. And a post going big in one community, can cannibalize all the other cross-posts due to de-duplication, meaning only one post gets the lions share of votes.
I've since changed my posting tool to actually make the various cross-posts at different times, instead of all at once.
This works well with my communities as art isn't time sensitive, and it's also kind of an excuse to re-post something a couple times, so different people can see it.