I’ve never heard of this. I know the school cancels, the work permit and the work permit is related to the extension of stay. And when you exit Thailand without a reentry permit, the extension of stay is automatically canceled anyway. I’ve had many extensions to stay (4+ now )but never gone to immigration to cancel them personally, because I thought they automatically cancel when you exit without a reentry permit. I’ve not had any problems.
then I suppose the extension of stay and overstay fine is only tied to the stamp in the passport then? because on the computer system...... i've already left the country and it should have automically cancelled the extension of stay.....I Then I entered on a visa exempt