How do limit orders on forex instruments work (or not)?

Based on my reading of the docs (API Version 1) performing a GET on this:

should result in an order to Buy to Open an initial position in EUR/JPY witha limit at the current market Q - 50 pips with a stop loss at the current market Q - 200 pips and a take profit at the current market Q + 200 pips. Is that right? In practice, sending this signal results in a market order immediately filled with the take profit and stop loss set at Q +200 and Q - 200, respectively. So, the limit part of the order appears to be ignored. What’s wrong with my reading of the docs?

Is anyone using the v1 API for limit orders on forex? Surprised no one has replied that they ran into the same issue.