SuperView Neo-1 01, a Chinese commercial imaging satellite launched in 2022, flies at about 513 km in a sun-synchronous orbit. On 1 October a Falcon 9 rideshare put 63 satellites and dozens of other objects into almost the same orbit, and they have been passing it ever since.

My tracker forecasts close approaches from Space-Track's public orbit data and re-runs them with every update. For OBJECT BF, one of the rideshare's objects Space-Track hasn't identified yet, every forecast from 25 October on put the pass at 20:24 UTC on 26 October, between 120 and 700 metres apart, at 72 metres a second. After the pass, fresh data re-measured it at about 130 metres.

That's finer than public data can really resolve. These orbits are good to around a kilometre, so the true miss could have been a few hundred metres or more than a kilometre, and operators get far better tracking and collision warnings than this. But it shows how crowded the 500 km shell has become. In the past day the same rideshare's satellites also passed within 2 to 6 km of PRSC-EO1, a Pakistani imaging satellite, three times, with another pass of about 1.3 km forecast for 28 October.

The pair's page has every forecast: https://overhead24.com/proximity/52320-100936