Dynamic Named Range Changing?

I am doing an Advanced Filter, and I am using a named range in my VBA code that decides the Criteria range.

The dynamic named range is called 'Criteria' and this is the code:

VB:
=OFFSET(Sheet1!$A$2,0,0,Sheet1!$BZ$23,41)

However, when I run the VBA code, although it works perfectly, afterwards the named range has changed to:

VB:
=Sheet1!$A$2:$AO$3

I just want this to remain unchanged, as it works great. This is my VBA code:

VB:
'Filter and send data to new sheet
Sheets("Sheet2").Select
Cells.Select

[Code]....