When the the Configuration File is modified using DM config File Customization Action from the PCK.AUTOMIC_DM action pack, the BOM mark duplicated in the modified file and it gets corrupted.
Extract from the action report:
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DMTool: INFO: ...File released after 0 attempts.
DMTool: BOM UTF-8 detected in file D:\temp\yyy\before.lst
DMTool: INFO: ...File released after 0 attempts.
***********DMTool: Reattaching earlier detected BOM at the beginning of the Text content*********
DMTool: D:\temp\yyy\before.lst: 4 change(s)
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Package Name: PCK.AUTOMIC_DM Package Version:1.4.2
This is a bug of the DM Action Pack
This bug is corrected in version 1.4.6 of the PCK.AUTOMIC_DM action pack which is available since February 1st 2022.
This version PCK.AUTOMIC_DM 1.4.6 contains some other fixes: