The delay in seeing your votes show up on submissions can be explained by some combination of the following two issues:

The first issue for you to consider is the continuous system load caused by immediately counting every single vote and/or flag on submissions. It makes a lot of sense to batch the tallying operations and only update every "N" minutes to reduce load. Additionally, since an up-vote on a submission will mark it so it's stored in your "saved stories" list, the overhead of immediate processing is most likely larger than most imagine. Also, there's the overhead and delays of multiple types of caching being employed. As always, it's a huge balancing act.

The second issue is how ring-voting, ring-flagging, and even ring-rating are constantly occurring since combating the problem is exceedingly difficult, and the rewards for successful abusive manipulation can be substantial. Abusive manipulation from multiple people/accounts is even more difficult to solve on any system designed to produce collaborative curation. Generally speaking, HN is collaborative curation, but attempts are made to prevent abusive manipulation.