Weird str manipulation of trigger info

[canderoc]

Sorry if this has already been addressed, but I couldn't find anything about it.
I was using this function:

Function Function3
Trigger $f 0xC48 "C:\Users\Nubbers\AppData\Roaming\Mozilla\Firefox\Profiles\ssho80ot.default"     

Code:

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function event $name [$newname]
;event: 1 added, 2 removed, 4 renamed, 8 modified
str s=name
out s
out s.trim("C:\Users\Nubbers\AppData\Roaming\Mozilla\Firefox\Profiles\ssho80ot.default\")

One event gave me this output, which is correct:
C:\Users\Nubbers\AppData\Roaming\Mozilla\Firefox\Profiles\ssho80ot.default\cookies.sqlite-journal
cookies.sqlite-j

But another event gave me this output:
C:\Users\Nubbers\AppData\Roaming\Mozilla\Firefox\Profiles\ssho80ot.default\sessionstore-1.js
-1.j

Why?