FGFNI and trailing backslashes

Is there any rule when FGFNI keeps a trailing backslash, for a non-root folder?

I’m seeing several cases for non-root folders, some having, some not
keeping the slash. None of them are SL_OPEN_TARGET_DIRECTORY opens.

Normalized file names. I think the behavior is tied to the folder not
existing, and FGFNI just keeping the slash.

None of them are SL_OPEN_TARGET_DIRECTORY opens

That would have been my guess… but might the filter manager’s cache have been primed with such an open? It might be an interesting experiment…

The file does not exist, there is nothing to cache.

I can confirm that this has only happened when the folder does not exist, and the passed in file name contained the trailing backslash, for now. I.e. I cannot confirm it cannot happen otherwise, but it is only in the case where the file does not exist that the trailing backslash is kept.