Sometimes there are known issues with some datasets which cannot be fixed but users should be aware of them with high priority to avoid related problems.

lfpw (MF)

• sea ice (ci) is available only up to day +60 in contrary to +61 for other params

ammc (BoM)

• wrong maximum values of surface_air_maximum_temperature_sfc at some points
  @Frédéric Vitart: The completely wrong max temperature from Australia in af ew coastal| grid points  is a know problem. I had an exchange of emails with the Australian about a year ago.  There is no quick fix since it is present in the re-forecasts and all the re-forecasts would need to be rerun. A possible solution was to mention in the Australian model documentation that tmax should be used only over land points (using ammc land-sea mask) since the problem happens only over sea points.
  @Richard Mladek:  it would be still beneficial to fix it as least for real-time forecasts