Master node has wrong trends_uint values for child's node's items.
In file nodehistory.c in function process_items there is something like this:
if (value_type == ZBX_TYPE_FLOAT)
DBadd_trend(itemid, value_double, clock);
else if (value_type == ZBX_TYPE_UINT)
DBadd_trend_uint(itemid, value_double, clock);
In my opinion should be:
if (value_type == ZBX_TYPE_FLOAT)
DBadd_trend(itemid, value_double, clock);
else if (value_type == ZBX_TYPE_UINT)
DBadd_trend_uint(itemid, value_uint64, clock);