HI Luis Chaves Rodriguez - Thanks for reaching out over Q&A Forum.
When it comes to SFTP storage events, ADF doesn't add that by default and need to be defined explicitly. This is documented in the below link:
If you're working with Secure File Transfer Protocol (SFTP) storage events, you need to specify the SFTP Data API under the filtering section too.
If you edit, it is like a re-deployment of trigger which overrides back to default setting i.e. no SFTP related API. Unfortunately, it is by design behavior.
Hope that helps!
Please let me know if there are any further queries/concerns, will be glad to assist.
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