Short answer. Yes. Article 766 protects mortgages made before your complaint for revocation is annotated in the Registry of Property. Even if the donation is later revoked for ingratitude, a mortgage the donee validly created before that annotation subsists; only mortgages made after annotation become void.
What the law says
Although the donation is revoked on account of ingratitude, nevertheless, the alienations and mortgages effected before the notation of the complaint for revocation in the Registry of Property shall subsist.
Civil Code, Article 766 — Effect Of Revocation On Third Persons. Read the full provision →
What the law says
Later ones shall be void.
Civil Code, Article 766 — Effect Of Revocation On Third Persons. Read the full provision →
Revocation for ingratitude does not automatically undo everything
You might assume that revoking a donation for ingratitude erases everything the donee did with the property in the meantime, but Article 766 draws a specific line based on timing. It states that "although the donation is revoked on account of ingratitude, nevertheless, the alienations and mortgages effected before the notation of the complaint for revocation in the Registry of Property shall subsist." Revocation reaches the donation itself, but it does not reach back to wipe out earlier transactions the donee validly entered into.
Why the annotation date is the dividing line
The critical moment is when your complaint for revocation was actually noted in the Registry of Property, not when the ingratitude occurred, when you discovered it, or when you filed the complaint in court. Before that annotation, third persons dealing with the donee — including a lender accepting a mortgage — had no way of knowing from the registry that the donation was under challenge, so the law protects transactions made in that window.
What happens to mortgages made after the annotation
The rule cuts the other way once the annotation exists. Article 766 states directly that "later ones shall be void." Any mortgage the donee creates on the property after your complaint has been annotated does not survive revocation, because from that point forward anyone checking the registry would have seen the pending challenge to the donee's title and taken the risk of dealing with the property anyway.
What this means for your specific situation
Since the mortgage in your case was created before your complaint for revocation was annotated, Article 766 indicates it subsists even after the donation is successfully revoked. Practically, this means that once you recover the property through revocation, you may recover it still subject to that mortgage, rather than free and clear of it. This makes the timing of your annotation critical in any future dealings with donated property you intend to revoke, since prompt annotation is what cuts off the donee's ability to burden the property with new encumbrances that would survive the revocation.