Logstash Dissect key modifier not working

[sandhyatallapanneni]

Hi There,

I am writing pattern in logstash version 7.10.2 or 7.15.2 for my log having different lines of pattern using Dissect filter with its key Modifier-> to remove space or spaces as per the log line before the next delimiter. But the Modifier-> is not working. Any suggestions? Please help

My log line is like below:

2020-07-03 14:49:02,003 INFO [org.jboss.as.ee] (MSC service thread 1-2) Configuring component class
2021-06-09 02:21:42,303 DEBUG [org.jboss.as.ee] (ServerService Thread Pool -- 56) Activating EE subsystem

My filter pattern with Dissect is like below:

filter {
        dissect {
mapping => { "message" => "%{logtime} %{+logtime} %{loglevel->} [%{modulename}] (%{thread}) %{logmessage}" }
}
    date {
                match => ["logtime", "ISO8601", "YYYY-MM-dd HH:mm:ss,SSS"]
    }
    mutate {
remove_field => ["path", "message"]
     }
}

I have two spaces after log level INFO and 1 space after log level DEBUG. So trying to use -> Modifier
Using grok I can get it working but want to know why is the Dissect Key Modifier -> failing and saying pattern not found.

Please help

Thanks!