ASM_REQUEST_DONE and HTTP_REQUEST_RELEASE issue

Hello

I have an irule where in the ASM_REQUEST_DONE event I am storing the ASM Support ID in a Variable and then in the HTTP_REQUEST_RELEASE event I am adding this variable to a HTTP header so we can follow the transaction though our platform. This generally works ok however around 10% of these on the HTTP_REQUEST_RELEASE the var is empty. I am running 12.0.0 HF2.

when HTTP_REQUEST_RELEASE {
if {[info exists x_asm_support_id]} {
    HTTP::header insert X-ASM-SUPPORT-ID $x_asm_support_id
    }

when ASM_REQUEST_DONE {
    set x_asm_support_id [ASM::support_id]
    }

Any one got any suggestions on how to make this work 100% of the time rather than only 90% of the time. To me it looks like a timing issue however I have tried using an "after x" in the else side of the info to pause for a few ms to see if I can get the data but this does not work.