Welcome to the Asana Community Forum @Martina_Tamvakou!
I have merged your post into a previous bug report regarding this issue.
Have you checked various tasks and it is not showing in any of them?
Also just to confirmed you have already that the “Convert task to template” is now showing below the other “Convert to” menu?
Some people do miss this as it shows separately and not within the existing menu. Richard has opened a feedback request thread about this here.