Here is the serialization of struct data which contains Vector(byte):

#pragma pack(push, 1)
struct OttMessage
{
uint16 descriptor;
uint16 msgNum;
int32 sec;
int32 nsec;

Vector<byte> data;

void Serialize(Stream& s)
{
s % descriptor % msgNum % sec % nsec % data;
}
};
#pragma pack(pop)


DUMP of buffer show the next:
(int)buf[0] = 102
(int)buf[1] = 0
(int)buf[2] = 111
(int)buf[3] = 0
(int)buf[4] = 123
(int)buf[5] = 0
(int)buf[6] = 0
(int)buf[7] = 0
(int)buf[8] = 222
(int)buf[9] = 0
(int)buf[10] = 0
(int)buf[11] = 0
(int)buf[12] = 7
(int)buf[13] = 10
(int)buf[14] = 144
(int)buf[15] = 56
(int)buf[16] = 233
(int)buf[17] = 77

Data from Vector begins since buf[12], but the value 7 unexpectable, it was not added to Vector.

When I change Serialize() as the following, then all data correct:

void Serialize(Stream& s)
{
s % descriptor % msgNum % sec % nsec;

for(int i = 0; i < data.size(); i++)
{
s % data[i];
}
}

(int)buf[0] = 102
(int)buf[1] = 0
(int)buf[2] = 111
(int)buf[3] = 0
(int)buf[4] = 123
(int)buf[5] = 0
(int)buf[6] = 0
(int)buf[7] = 0
(int)buf[8] = 222
(int)buf[9] = 0
(int)buf[10] = 0
(int)buf[11] = 0
(int)buf[12] = 10
(int)buf[13] = 144
(int)buf[14] = 56
(int)buf[15] = 233
(int)buf[16] = 77
(int)buf[17] = 188

Can anyone explane such strange behaviour?
Why I need to add Vector data one by one?