what do you mean by "it doesn't register the corisponding move on payment of the expense"?

On paying the expense it should create the accounting move to move the tax from the holding account to the tax account.

It does this correctly on an invoice but doesn't do it when paying an expense.

If you mean in creating a payments( below invoice), a payment is made as one transaction. Not one for products and one for tax

I'm aware it's as one accounting transaction. The first journal created when an invoice is created - creates the lines for base amount and tax - with the tax moved to the tax holding account.

The journal entry when a payment is made - moves the tax from the holding account to the tax account - this is the correct and expected behaviour on invoices.

On expenses - when the expense is paid it does not move the tax from the holding account to the tax account.