The difference between these 2 colors is huge and while there can be sometimes some visible difference in colors between the Ajax Client and Desktop/Plugin but this much is strange.
There should be something going wrong!
Which version of Qlikview you are using? (Server and Desktop are recommended to be of same version)
Also, are you using calculated colors?
Are you using transparency in colors?
If you can post your qvw then it will be easier to see what is going wrong!