Currently, if there's a like on a post and then you delete the post, the notification stays in your notifications feed. Clicking on the bold "your post" text just takes you to your 'follwed users" feed. The notification for the deleted post is useless and adds a bit of confusion in the notifications feed. Therefore, when a post is deleted, the notification should be deleted too.
I suspect that the record of the like still shows up in "your liked posts" as well, but I haven't confirmed that yet.