I have experienced the same issue for me the temporary solution was to uninstall the DLP content from the Server where you ran the Browser from then launch the the Browser to the other version of ePO & DLP then it will do the download again for that version so no it is not compatible with other versions at the same time.
1 way around this is to launch the Console from 3 different Servers so you have 1 version running from each Server if this helps you then you can have all 3 running from independent remote Servers or run it from the Remote Desktop of each ePO Server so everything is self contained to each ePO Server.
Thank you for your quick response. That is precisely what I was understanding too. I will have to do that until I can get them to all upgrade to the same ePO. Maybe now I can present them another business case to do so.
Best option is use all 3 DLP console from different machines, issue will fix