Bizarre lag like movement.

@MandatoryIDtag What do you mean by "there are no issues on their end"? Are you spectating them, watching their stream, are they your teammates or friends that tell you how it looks on their end?

I've seen similar stuff, enemies that move smoothly and start stuttering after they get shot at. There can be different reasons for this. For example, if someone is moving in a straight line, with constant speed, the interpolation makes it appear very smooth even if that person has an unstable connection to the server. But when they start jumping and changing directions, the simulation will not look that smooth anymore. I'm not excluding hacks, maybe a soft DDoSing or something that chokes their upload bandwidth just right.

@MandatoryIDtag You mean like the wraith glitch people were doing last season abusing her ultimate to gain speed? They looked like they were glitching too.

@MandatoryIDtag I dunno. Clip it next time.

@MandatoryIDtag Interpolation is used to build the frames between the updates you receive. If the server sends you 20 updates per second, interpolation is used to build the other 40 frames in between so you get that 60 fps. Everything would feel jumpy without interpolation, like playing at 20fps.

For interpolation to work, some buffering needs to exist (a few frames), so that enough data is gathered to make the simulation smooth. But this buffer adds lag, so it needs to be as small as possible. Therefore, I think they set the buffer depending on the connection you seem to have. If you are apparently on a strong connection, the buffer will be small. The problem is when some congestion appears and your connection gets worse, with lag spikes and lost packets. I think the game increases your buffer when it detects this, in order to stabilize things, but, during the time it takes to rate your current connection, some issues do happen, like stuttering / teleportation.

Lag compensation is different. You shoot someone but, when your shot data reaches the server, the target is not where you saw it a few milliseconds ago, so the server interpolates between past updates to determine where the target was at the moment you fired your shot, in order to confirm or decline your hit.