same here w/ freshly installed LO 2019 and natively created drawing exported to DWG v2018.
A known bug of the ODA Teigha SDK introduced with the initial support of the AC file format version 2018 in the Teigha version 4.3.1. A patch for the version 4.3.2 used by SU 2019 is avail., the latest Teigha release version 2019 does already include the fix.
Should make it in an initial SUP 2019 maintenance release.