Sales reps unable to see personal views after moving BU

[bs-dev001]

There was an organization change in our firm and a couple of sales reps needed to move to a new business unit.  We followed the guide line (https://docs.microsoft.com/en-us/power-platform/admin/create-edit-business-units), created a new BU and moved them to it.

Surprisingly, the sales reps reported they no longer see their personal views in Model Driven app.  Not to mention, this is such a business impact so we immediately moved them backed to the previous BU.  Just to add more information, all the sales reps, regardless of BU, have the same role which is exactly the same as what it was before moving BU.

Can someone from Microsoft help to shed some light on?  How come moving BU affects visibility of personal views?