Question about triggers initiation

[ssimop]

I would like to know which macro or system routine checks for triggers' validity, just after init2 is initiated or short time afterwards and I get the following error message in output :

Failed to start file trigger of <open>FolderCreated. Trigger: $f 0xC04 "%SESdoc%". Time: 0 ms. Error: The system cannot find the file specified.

I found a way to empirically overcome this problem by setting the value of environment variable %SESdoc% early in init2. But still, a professional solution request an answer to this question.

Many thanks.