This vehicle is merging into traffic. Is it doing so correctly?

As a general rule, driving in reverse is prohibited, except in the following cases on an exceptional basis and always with the minimum essential distance: 1. As a complementary manoeuvre to stopping, parking, or merging into traffic. In this case, the reverse distance cannot exceed 15 metres nor invade an intersection. 2. When it is not possible to move forward or change direction or direction of travel. In this case there is no limit on the reverse distance, even invading an intersection if necessary. The reverse manoeuvre is prohibited on motorways and dual carriageways. In the case of the question, since it is merging into traffic, it cannot travel more than 15m or invade an intersection, so what the blue vehicle is doing is incorrect.