FilteringUtils.escapeWindowsPath doesn't handle paths that leave out the drive letter.

FilteringUtils.escapeWindowsPath requires a drive letter to be present in the path, or at least the string

":\\"

to be present in order to trigger escaping the value as a windows path.

In cases where the path is an absolute reference to a file on the current drive (no drive letter is included), or when the path starts with an unresolved expression (in cases where n+1 level interpolation will eventually resolve the expression), escaping doesn't happen at all.