SelectionMode FullRowSelect

Happy New Year all..

We have an odd discrepancy with a couple of DataGridViews on two respective pages that are behaving differently.

When a row is selected let’s say a cell click event or row header event identified
the RowIndex, and sets the “current” row as selected.
One page sets the Style.BackColor to the Color.Value I see in the theme file LightBlue.

Another page using the SAME theme when a row is “selected” (same process as previously described)
refuses to implement the Style.BackColor to the Color.Value from Theme file.

I have dug into the Style.BackColor of BOTH to confirm the current values WHILE SELECTED!
as I cast the DataGridViews SelectedRow[X] to a DataGridViewRow and confirm the Style.BackColor
of its cells or just go through the DataGridViewRow itself and check the Style.BackColor of its Cells

I just don’t understand one grid displays the proper Style.BackColor
Color.Value in the cells whilst the other refuses to.
Again Note I confirmed that NEITHER will list as I debug them that Style.BackColor as correctly assigned
to the cells even the one properly displaying the back color.
I’ve attempted to mirror various other properties of the DataGridView,
MultiSelect = true not listed in Designer File at all
SelectionMode = FullRowSelect not in Designer File at all
RowHeadersVisible = true
EditMode EditOnKeystrokeOrF2
AutoGenerateColumns Not Present

BOTH IMPLEMENT .Columns.AddRange

The only difference I can identify is the datasource for each.
The DataGridView that is updating its Row with Cell BackColor LightBlue its DataSource is a
System.Collections.Generic.List<SomeEntityObject_FromEntityFramework>
While in Contrast the non functioning one is a just a plain DataTable

This is too grandiose to whip up a sample project for you,
I suspect I couldn’t replicate the differing behavior if I tried in a test solution.