How to add support for segwit address and legacy with bitcoin core 0.16?
Quoting Suhas Daftuar's response to the issue you opened:


  In 0.16, we changed the consensus parameters for regtest so that segwit was always active. This was mentioned briefly in the release notes https://github.com/bitcoin/bitcoin/blob/v0.16.0/doc/release-notes.md#testing-changes, along with a workaround to replicate the old behavior.
  
  I am surprised that you're not seeing the assertion failure mentioned in the release notes, but I suspect this is the cause of what you're seeing.


So this is expected, but only affects regtest.