CloudFlare has fixed the problem on its side as noted here :
https://community.cloudflare.com/t/error-stream-error-in-the-http-2-framing-layer/699319/5?u=a1115

Only customers using curl were concerned. As BetterStack is using curl it was reporting downtimes that were not seen by our customers

False positive confirmed. Our customers were not affected.

BetterStack shows connectivity issues to our API but it seems the problem is from BetterStack and noton our side. We are investigating.