Indonesia is a big country with over ten thousand islands and uneven coverage. What is blocked on one ISP might not be enforced on another (e.g. the state-owned ISP might block or use DNS poisoning on several "non-compliant" DNS providers but my current ISP doesn't). Also, in addition to what the sibling commenter (and another commenter regarding Cloudflare outage) said there might be a general overload on the mobile network near the affected areas since there are lots of users and limited bandwidth.