Could you provide a concrete example?
Intuitively I do understand ClojureScript is not as seamless as some people say. First of all, Clojure is kind of a database-programming language with fundamental data types built around concurrency, while JavaScript was single-threaded until recently (and web workers used shared-nothing model). Second, Clojure is build around Java specifically, not any other language. Java has some strict type system with immutable complex objects being pretty much native way of doing things, thus Java is great for implementing dynamic types on top of it.
But I feel like not having undeniable proofs of fundamental flaw in ClojureScript. For example, JavaScript fundamentally lacks copy-on-write complex structures. Thus development of copy-on-write libraries is painful e.g. ProseMirror which can become completely broken until page reload which is bad for Single Page Application. However, could it be that ClojureScript... just works?