Security Level not being assigned with post-function on create transition

[Edgar Oregel]

Issue:

I'm trying to set the Security Level of a ticket using a post-function on the create transition, but the field doesn't get assigned when it's created.

Details:

I'm using the post-function by JWT "Set a field as a function of other fields" where i check the issuetype field against a string and assign the Security Level if it equals the string value. I triple checked that the project is using the Security Level Scheme and i'm giving a valid value that exists in the scheme, I have permissions to set Security Level when creating ticket, and i've tested putting the post-function as the very first one to run before the "Creates issue originally" internal JIRA post-function as well as after the post-function. 

Any idea what i'm missing?