i had major issues with lein 2.8.2 involving nrepl. I had to revert back to 2.8.1.

✗ lein repl
OpenJDK 64-Bit Server VM warning: Option UseConcMarkSweepGC was deprecated in version 9.0 and will likely be removed in a future release.
Exception in thread "main" java.lang.AssertionError: Assert failed: transport-fn, compiling:(/private/var/folders/nr/8vbdczz90ps9zfrklvm8jfwm0001yl/T/form-init7457278500009733573.clj:1:125)
	at clojure.lang.Compiler.load(Compiler.java:7526)
	at clojure.lang.Compiler.loadFile(Compiler.java:7452)
	at clojure.main$load_script.invokeStatic(main.clj:278)
	at clojure.main$init_opt.invokeStatic(main.clj:280)
	at clojure.main$init_opt.invoke(main.clj:280)
	at clojure.main$initialize.invokeStatic(main.clj:311)
	at clojure.main$null_opt.invokeStatic(main.clj:345)
	at clojure.main$null_opt.invoke(main.clj:342)
	at clojure.main$main.invokeStatic(main.clj:424)
	at clojure.main$main.doInvoke(main.clj:387)
	at clojure.lang.RestFn.applyTo(RestFn.java:137)
	at clojure.lang.Var.applyTo(Var.java:702)
	at clojure.main.main(main.java:37)
Caused by: java.lang.AssertionError: Assert failed: transport-fn
	at nrepl.core$connect.invokeStatic(core.clj:168)
	at nrepl.core$connect.doInvoke(core.clj:168)
	at clojure.lang.RestFn.invoke(RestFn.java:457)
	at nrepl.ack$send_ack.invokeStatic(ack.clj:45)
	at nrepl.ack$send_ack.invoke(ack.clj:41)
	at nrepl.server$start_server.invokeStatic(server.clj:146)
	at nrepl.server$start_server.doInvoke(server.clj:105)
	at clojure.lang.RestFn.invoke(RestFn.java:1096)
	at user$eval39983.invokeStatic(form-init7457278500009733573.clj:1)
	at user$eval39983.invoke(form-init7457278500009733573.clj:1)
	at clojure.lang.Compiler.eval(Compiler.java:7062)
	at clojure.lang.Compiler.eval(Compiler.java:7052)
	at clojure.lang.Compiler.eval(Compiler.java:7052)
	at clojure.lang.Compiler.load(Compiler.java:7514)
	... 12 more

It's already been reported here: https://github.com/technomancy/leiningen/issues/2497

Mine was on MacOS

@dcj this affects leiningen in all OSes. It was an issue with nREPL.

Made a quick video about using Figwheel-main + Clojure CLI + CIDER : https://youtu.be/hcFx-QL5ySM