Unable to add absence reason explanation on Add absence page

Hello,

On the Add leave screen, when absence type is selected and absence reason is selected, I want a description to appear below the reason. For this I added a field with Html markup.

But even if I change the reason for absence, the description field does not change.

and when I enter the page again to enter a permission, the explanation of absence reason never comes up.

The code I wrote is as follows :

#{bindings.AbsenceTypeReasonId.inputValue==300000020656397? '<b> 3 working days for each birth at home.</b>':''}

what could be the reason for this?