Some files, such as the main shim, the deps.js and such are non-reloadable. Boot-reload will still try reloading those if they change which happens when changing :require on cljs.edn: boot-clj/boot-cljs#108

This usually causes follwing exception:

Failed to execute 'write' on 'Document': It isn't possible to write into a document from an asynchronously-loaded external script unless it is explicitly opened.

This would be fixed by using Figwheel client.