Discrepancy in logstash timestamp output and kibana

Elastic Stack Logstash
7

This is my complete conf file.

input {
file {
path => "/tmp/stats/flowStats.csv"
start_position => "beginning"
}
}

   filter {
csv{
separator => ","
columns => ["Broker Name","Flow Name","Flow UUID","Record Start Date","Record Start Time","Record GMT Start Timestamp","Record End Date","Record End Time","Record GMT End Timestamp","Average CPU Time","Total Number of Input Messages"]
   }
mutate {
rename => { "Broker Name" => broker_name }
rename => { "Flow Name" => flowname }
rename => { "Total CPU Time" => cputime }
rename => { "Total Number of Input Messages" => input_messages }
remove_field => ["message","Flow UUID","Record Start Date","Record Start Time","Record GMT Start Timestamp","Record GMT End Timestamp"]
add_field => {
"timestamp" => "%{Record End Date} %{Record End Time}"
}
remove_field => ["Record End Date"]
remove_field => ["Record End Time"]
}
date{
match => ["timestamp","yyyy-MM-dd HH:mm:ss.SSSSSS"]
timezone => "America/Chicago"
}
mutate{
remove_field => [ "timestamp" ]
}
}
output {
stdout { codec => rubydebug }
file {
path => "/tmp/flwstats.csv"
}
}

I really don't know what i am doing wrong.