Block names doesn't matter. At some point I plan to rename the word "position" with "trade" for MT5.
Your MT5 account should be opened with this checked:
0_1528204153847_03f0bb20-ac08-4797-9ca1-43de3b9070fe-image.png
... otherwise it is working in Netting mode, which means that you can only have 1 position per symbol. This is something that can explain immediately closed trades, because if you Buy and then Sell the same lot size, the result is that the initial Buy position is closed.
If your MT5 account is in Hedge mode, then the problem could be because of some bug that I am not aware of. In this case I want to investigate the problem, so if you have some relatively simple example that shows the problem, give it to me 🙂