Documentation not generated when a candidate package is corrected and re-uploaded

I noticed that Haddock for a given version number is generated only once even if the package having the same version is uploaded again after some correction. For a given version hackage always uses the haddock generated on first upload. If the new upload has an additional module, the new module will not have its haddock generated. If the new upload changed documentation it will not be reflected.

I tried deleting the previous candidate before uploading the new but it did not work. As long as the version remains the same it still picks up the old documentation.

To avoid this issue I had to change the version number of the package and then upload a candidate with new version.