Chrome prefetch breaks APM sessions?

When using the following CLI command "load sys config from-terminal merge" to copy the whole iRule with the code submitted by Stanislas, we got the following warning under build BIG-IP 12.1.3.6 Build 0.0.3 Point Release 6. This error is not caught under the configuration utility.

when ACCESS_SESSION_STARTED { if {[HTTP::header Purpose] equals "prefetch"} { ACCESS::respond 403 -version "1.1" noserver "Connection" "Close" ACCESS::session remove return } }

warning: [The following errors were not caught before. Please correct the script in order to avoid future disruption. "unexpected token(s): ' Connection Close'"1146 65][ACCESS::respond 403 -version "1.1" noserver "Connection" "Close"]

Should we be worries about it?