G/L Register VAT entry no keep on updating even there is no VAT entry

why these VAT entry from/to keep always last posted entry for all next G/L registers? it should be blank? is it bug or intentionally keep on updating even there is no VAT related entry?

They will be created as long as you have any VAT releated setup on your G/L Account. That enables the system to report on VAT posting groups that does not necessarily calculate any VAT but might be needed for regulatory reporting.