I think I found a bug in one of the include files that come with MT5: Its in class COrderInfo (file trade\OrderInfo.mqh) line 194.
Below code is an excerpt from this file: lines 171-199. The bug is in method TypeTimeDescription(). As you can see it returns the wrong data namely the same as method TypeFillingDescription() does. In the snippet below you can see that I commented the wrong code and inserted the (in my opinion) correct code.
Unfortunately I have no working example that shows the effect of this bug. sorry for that.