"Section 6 A foreigner who is entitled to benefits under Section 3, Section 4, and Section 5 must meet qualifications and comply with rules, procedures, and conditions as prescribed by the Director-General of the Revenue Department.
Section 7 In the case that a foreigner has applied tax reduction or exemption under this Royal Decree, and later does not comply with rules prescribed in Section 3, Section 4, Section 5, and Section 6 in any tax year, benefits will be suspended in that tax year."
That's what we know, but IMHO it could mean that if you omit to file a tax return the LTR exemption doesn't apply for the relevant year.