So RO works fine. Problems with either resin or your vessel. In past i used a 20" blue vessel which had a cartridge inside which i filled with di resin. But i over tightened it, which rendered the cartridge useless as it was bypassed. The water came out at same tds as what went in. This could be similar to what your experiencing. If its fresh resin your using and the water going in is only 008, then it would be safe to say its the di vesel where the problem lays. Check the inlet and outlets, are you fully filling and compacting the di in the unit. Sorry for silly/obvious but make sure the water from ro is entering correct inlet on di.
In addition, you are also good to use water at 008 for cleaning windows.
Hope this helps n u identify problem