New propane change over regulator leaking

[scottz]

My son is having a problem with his RV. His ran both his propane tanks empty and replaced tank one with a full tank. The change over lever is pointing at tank one (full tank), tank two is still disconnected pending getting another full tank. When he turns tank one on, gas comes out tank two’s disconnected line. He tried moving the change over lever back and forth a couple times; no help. I figured the change over regulator was bad and advised ordering a new one along with new pig tails. He did this, installed the new parts and still has the same problem. This RV has both tanks in front, sitting side by side with the change over regulator between them. It does not have a pressure reducer like our Montana’s have with opposite side tanks. Any idea what the issue is? I'm wondering if both the original and the new change over regulator are defective?