Server can't parse cookie

Question

I noticed the following messages in my TJWS log.

[Mon Oct 03 21:28:28 EDT 2016] TJWS: An exception in parsing cookies: id=die(pi());; user=assert
java.lang.IllegalArgumentException: Cookie name "; user" is a reserved token
    at javax.servlet.http.Cookie.<init>(Cookie.java:192)
    at Acme.Serve.Serve$ServeConnection.addCookie(Serve.java:2812)
    at Acme.Serve.Serve$ServeConnection.parseCookies(Serve.java:2787)
    at Acme.Serve.Serve$ServeConnection.runServlet(Serve.java:2398)
    at Acme.Serve.Serve$ServeConnection.parseRequest(Serve.java:2330)
    at Acme.Serve.Serve$ServeConnection.run(Serve.java:2110)
    at Acme.Utils$ThreadPool$PooledThread.run(Utils.java:1238)
    at java.lang.Thread.run(Thread.java:745)

/185.129.148.216:443 - - [03/Oct/2016:21:28:28 -0400] "GET / HTTP/1.1" 200 20,280 - -

Should I start worry and report a bug in the server?