New SDS011 Sensor reading very high

Recently had to replace a SDS011 sensor and esp board after the existing one had water ingress and stopped working. Replacement works and connects to network but reads very high (600 - 700 PM 2.5) is it likely to be a faulty sensor or is there some other fix?

Note; I have 4 other sensors co-located and all read normal levels (2- 50 PM2.5) and the newly flashed esp board works fine with one of the other sensors reading normal.

Faulty sensor. The Laser has shifted or is half disconnected. It is possible to repair but complicated. I did it once but it is not worth