Problem with asynchronous reading from a mailslot

We (Linter) found another problem with reading from a mailslot.

Steps to reproduce:

1. Create a mailslot.

hMailslotClient = CreateMailslot(LMS, 0L, MAILSLOT_WAIT_FOREVER, 

(LPSECURITY_ATTRIBUTES) NULL);

2. Attempt to read asynchronously (parameter lpOverlapped not NULL) from the slot

ReadFile(hMailslotClient, lpszBuffer, LENMSG, &cbRead, &stOverlapped)

3. Function ReadFile() must return value immediately (with code ERROR_IO_PENDING), but this does not happen

Example available here:
https://github.com/pechenkin/mailslotBug/blob/master/mailslotBug2.c