Last time I developed mobile apps that depended on consistent webview functionality, Android went a step farther: Android vendors could replace the webview provider with something custom, and some did (Samsung, at the time, notably and impossible-to-ignore since they're huge). Not only might you not get a particular version of Chrome/Blink providing your webview—you might get any engine. There were basically no guarantees at all.

The result was that the only way to obtain non-crazymaking behavior and bug report loads on Android, if you needed a webview or even just a javascript engine, was to bundle your own thing. IIRC we ended up bundling a JS engine to get around the worst of it, for what we needed—might have been a full browser we bundled, can't recall for sure. We encountered multiple real problems in the wild trying to use the built-in engine(s). On iOS, we both couldn't bundle our own JS or browser engine (by policy) and... had no need to, since that never caused many problems.

It's one of of several reasons that, while Android developent was probably easier even then at a hobbiest level than iOS was, it was a much bigger pain in the ass to support & develop for at any kind of scale. But, that was a while ago—maybe it's gotten better.