RTOS/DK-TM4C129X: Task blocked on an unknown semaphore (with a label same as the task label)

Part Number: DK-TM4C129X

Tool/software: TI-RTOS

Hello

I am trying to utilize USB re-connection.

I have a task that handles all the USB Tx. 

It sits of a mailbox, pending until a message pops up, and sends it through the usual USBDCDC handlers.

after disconnecting the cable, the "message" task is blocked by "message" semaphore, which appears in the ROV only then.

the mailbox is empty, and I am calling semaphore_post to release the USB_Tx semaphore.

I would appreciate any help.

code:

while(1)
{
Mailbox_pend(msgQ , &Message, BIOS_WAIT_FOREVER);

SendResponse(Message.messageId);

....

}