See - 172509.pdf
"x x x.
We deny the right of the BIR to collect the assessed DST on the ground of prescription. Section 1, Rule 9 of the Rules of Court expressly provides that:
Section 1. Defenses and objections not pleaded. -
Defenses and objections not pleaded either in a motion to dismiss or in the answer are deemed waived. However, when it appears from the pleadings or the evidence on record that the court has no jurisdiction over the subject matter, that there is another action pending between the same parties for the same cause, or that the action is barred by prior judgment or by the statute of limitations, the court shall dismiss the claim. If the pleadings or the evidence on record show that the claim is barred by prescription, the court is mandated to dismiss the claim even if prescription is not raised as a defense.
In Heirs of Valientes v. Ramas, we ruled that the CA may motu proprio dismiss the case on the
ground of prescription despite failure to raise this ground on appeal. The court is imbued with sufficient discretion to review matters, not otherwise assigned as errors on appeal, if it finds that their consideration is necessary in arriving at a complete and just resolution of the case. More so, when the provisions on prescription were enacted to benefit and protect taxpayers from investigation after a reasonable period of time.
x x x."
