I play on the Facepunch Official Texas Server and very frequently (probably around once a minute during more peak time) the server will seem to pause. All other players stop moving, and interacting with anything is impossible. During this time, you can still move around and deal damage and/or kill people. Abusing this correctly, you can wait for the pause, peek a corner and kill someone without them having any way to fight back (unless they do the same). Once the server un-pauses (usually after a couple seconds), you get teleported back to where you were when it paused, and any damage seems to still count. You can very often go from full health to dead without anything happening on your end because of this. This tends to get worse after the wipe slowly, but its already gotten pretty bad this cycle.
Certain patches have been better for this, but it really makes playing the game quite frustrating. You often times get warped back through doors, or have trouble opening boxes/etc. I imagine a lot of people experience the effects of this, but mistake it for other issues frequently. Possibly that someone is cheating, or they are lagging or whatever.
Personally for me this is one of the biggest issues impacting the game right now (this and the cheating problems). I understand that there are certainly performance issues with an alpha, but this seems like it might be something else. Maybe when the server is saving the state or something? Since everything is able to run reasonable fine 95% of the time, its just that 5% where everything pauses.