We have just released snowplow-fractribution v0.3.6 which is a small patch that fixes an issue for users who want to use the inferred dates for their conversions.
Summary
Fixes an issue with the window calculation when start/end dates are not specified.
Upgrading
Bump the snowplow-fractribution version in your packages.yml file. It may be an hour or two before this release is available on the dbt hub.