According to the Cloudflare documentation, it is stated that dynamic URLs are not eligible for caching and return 'DYNAMIC' for the 'cf-cache-status'.
$ curl -sI https://play.carimbo.cloud/0.0.70/flippingpixels/wiggler/0.0.22/480p/carimbo.wasm | grep cf-cache-status
cf-cache-status: DYNAMIC
Same URL for JavaScript
$ curl -sI https://play.carimbo.cloud/0.0.70/flippingpixels/wiggler/0.0.22/480p/carimbo.js | grep cf-cache-status
cf-cache-status: HIT
Why is Cloudflare not caching WebAssembly? WebAssembly is considered a web resource.
Solved with a Page Rule
play.carimbo.cloud/* Cache Level: Cache Everything