Cell value leaking into other cells when entering new value

In the Frozen Column Example, when entering a new value for a cell that exceeds the length of the cell, the value will leak into other cells without any changes being made to the original cell. After you have confirmed the value, for example by pressing enter, the cell goes back to normal and the value is no longer leaking into the other cells.

Expected behavior:

The cell should join when the value starts to exceed the length of the cell, expanding with the value. This image was taken in 6.6.1.

Observed behavior:

The value is leaking into other cells without the cell expanding. This image was taken in 6.7.0.