Yes, that is a known bug we couldn't figure out yet why that happens. You can try either respawning or running against an object so the enemy isn't stuck on you anymore. We are also still trying to figure out what causes the lag spikes, we improved performance and hoped it was fixed but seems like not, thank you for telling us.
Yes, understandable that you don't know where to hit without an indicator. We will look into it and see how we can implement an indicator for the enemy hitbox.
Thank you very much for your feedback!