Why is Logback appending time-since-start counter at start of all statements?

Question

Here's a simplified version of my logback-spring.groovy (supported by spring boot)

import ch.qos.logback.core.ConsoleAppender

import static ch.qos.logback.classic.Level.INFO

appender("Console-Appender", ConsoleAppender.class) {
    encoder(PatternLayoutEncoder) {
        pattern = " %d %-5level [%thread] %logger{30}: %msg%n%r"
    }
}

root(INFO, ["Console-Appender"])

Here's my log

 2016-08-29 19:14:41,062 INFO  [restartedMain] something....
1780 2016-08-29 19:14:41,066 INFO  [restartedMain] something...
1784 2016-08-29 19:14:41,160 INFO  [restartedMain] something...

There's a number at the start and I think it's milliseconds-since-start and I'm unable to figure out how to turn that off.