ID 462670 - Array widget IndexError when reducing the array size and the row slider is outside the range

Problem summary
Array widget <IndexError>​when reducing the array size and the row slider is outside the range. The Attributes tab is also affected. 

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Customer reported version
4.0__4.0v1

Customer reported platform
centos7

Steps to reproduce

1) Create an AttributeSet node
2) Set the numberValue parameter of the AttributeSet node to a 8x1 array
3) Slide the row slider down
4) Set the numberValue parameter to a 3x1 array

Expected behavior
The numberValue parameter array is committed without any errors. 

Actual behavior
Some numberValue parameter array elements contain <IndexError>. The Messages tab prints:

getArrayChild(): Invalid index: 3    ArrayParameterPolicy    2020-12-11T07:17:32

Workaround
Increase the size of the numberValue parameter array, then slide the row slider all the way up.

Reproduced by support
This bug has been reproduced in:
Katana 4.0v1 - CentOS 7, Windows 10
Katana 3.6v3 - CentOS 7, Windows 10
Katana 3.6v1 - CentOS 7, Windows 10
Katana 3.5v4 - CentOS 7, Windows 10
Katana 3.5v1 - CentOS 7, Windows 10
Katana 3.2v6 - CentOS 7, Windows 10
Katana 3.1v1 - CentOS 7, Windows 10
Katana 3.0v1 - CentOS 7, Windows 10
Katana 2.5v1 - CentOS 7, Windows 10
Katana 2.0v1 - CentOS 7
Katana 1.6v3 - CentOS 7

Earliest version tested
Katana 1.6v3 - This issue appears to be in all versions of the product