Each time avatar enters/leaves sim (by teleporting or logging in/out) sim stops responding (no ability to move, scripts freezes etc) untill that avatar finishes teleporting or logging in/out.
It gives the impression that internet communication with server for that time is down or server sleeps. It is especially noticable in sims with high people flow (very often entering or leaving).
I only noticed it on private islands, i don't know if that happens on mainlands as well.
Restart of the sim doesnt help, it happens each time someone enters/leaves without single exception.
It happens in my sim Odessa Renowned, but was noticed in many other sims by different people using different browsers and operating systems.
First time was noticed a couple months ago after adult content beta introductions and single avatar lag listings in "Get Top Scripts" window intorduction.
It might be a bug caused by adult content checking when someone enters sim/leaves sim.
When you have high flow in your sim (like every 1-2 minutes someone enters/leaves) and each time sim stucks for 10-15 seconds it makes whole sim useless so i hope something will be done with it.