src/Queries/SectionQuery.php
protected function normalizeSelect()
    {
        if ($this->fieldsMustBeSelected()) {
            $this->select = array_merge($this->standardFields, $this->select);
        }

        if ($this->propsMustBeSelected()) {
            $this->select[] = 'IBLOCK_ID';
            $this->select[] = 'UF_*';
        }

        $this->select[] = 'ID';

        return $this->clearSelectArray();
    }
protected function normalizeSelect()
    {
        if ($this->fieldsMustBeSelected()) {
            $this->select = array_merge($this->standardFields, $this->select);
        }

        if ($this->propsMustBeSelected()) {
            $this->select[] = 'IBLOCK_ID';
            $this->select[] = 'UF_*';
        }

        $this->select[] = 'ID';

        return $this->clearSelectArray();
    }
Normalize select before sending it to getList.
This prevents some inconsistency.

@return array