Hello - I have not used custom visuals in a while (previous owners did not allow it).
Our new owners do, and I was building a brand new report (new pbix file with June 2022 version). I added the Chiclet slicer and also the Histogram visual (pinned them). All was good for a while. Then, after building the report for a while I noticed that both of the visuals disappeared. The container box for them was still there in the report, but empty. I've since reproduced this issue multiple times but it's hard to do so because it is just a random event. I can't give any specifics as to what causes it to happen. But it does indeed happen.