Can a successful party be deprived of their costs or even ordered to pay costs?

Rule 24(4) provides that in some circumstances a successful party can be deprived of their costs – or even ordered to pay costs – if they have behaved unreasonably. Ajiboye v. Ajiboye 2019 ONCJ 894 (OCJ). However, since I have determined that the mother acted entirely reasonably, there is no basis for any reduction of the costs she would otherwise be entitled to.