The Infraworks 2019.3.1 Hotfix is available via the Autodesk Desktop App or via download from the Autodesk subscription site.

The update install requires access to the install original 2019 product resources.

Infraworks 2019.3.1 Hotfix

As per the usual your Models must be updated to this new build of Infraworks.

New Infraworks 2019.3.1 Hotfix Fixes

Civil Structures

• Fixed an issue where girders with plinths were not properly fitting with the bridge deck, given various lateral offsets.

Model Builder

• Fixed an issue where users of Autodesk InfraWorks 2019.3 (February 2019 release) were unable to create local models with the Model Builder if they did have a BIM 360 account.
  Please note: After you install this hotfix, all Model Builder models will be downloaded locally. Once you create a local model, you can publish it to BIM 360 Document Management using the Publish tools in the InfraWorks utility bar.

See the Infraworks 2019.3 Update release notes