Shift space does not select the full row in Google Sheets, only a part of it

In Google Sheets, if I select a cell and then SHIFT+Space I expect the entire row row to be selected however sometimes only part of the row is selected and I need to press SHIFT+Space again.

For example:

1. I select a cell:
    

2. I press Shift+Space but only part of the row is selected:
    

3. I press Shift+Space again (or just Space if I haven't yet released Shift) to select the remainder of the row:

I found a LinkedIn post where Ben Collins says the following:

Here's the shortcut to select a whole row in Google Sheets:

Shift+Space Bar

Note: if you use this when your cursor is inside or next to a filleddata range, it will only highlight the row within that range. Press itagain to extend to the whole row.

Despite his 'note', I see different behavior since my first selection finishes with two blank cells and I'm confused as to whether internal ranges are forcing the selection to end where it does and I need to remove them.

Is there a way to select the entire row the first time?