Identity the source of the exception whose signature is below.  It is found in the SMX logs.

2020-09-25 06:01:29,488 | WARN  | p418182037-21044 | AbstractHttpConnection           | 49 - org.eclipse.jetty.aggregate.jetty-all-server - 8.1.19.v2016020
9 | *                                                                                                                                                       
java.lang.StringIndexOutOfBoundsException: String index out of range: -1                                                                                    
       at java.lang.String.substring(String.java:1967)[:1.8.0_261]