Collection variable setting not works in manual execution

Hello,

I have a script which sets a collection variable after parsing the value.
Based on the console log it seems that value can be read successfully.
Though when I open the collection variables after the request, I can’t find the collection variable value filled in.

I have tried also to set collection variable value with a fixed value. The collection variable is created but value is not added.
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Oher collection variables can be set in the pre-request script successfully.

What could be the reason?

Thanks!