**Please make sure that this is a bug! If you have questions about how to use TwoSampleMR please use the [Discussions](https://github.com/MRCIEU/TwoSampleMR/discussions) function instead.** ## Describe the bug (required) *Provide a clear and concise description of what the bug is* ## Describe the current behaviour you observe (required) *Include code blocks with any error messages* ## Describe the behaviour you expect (required) ## R code to reproduce the issue (required) *Please provide a minimal code snippet that will reproduce this issue* ## Contribute a solution (optional) Please submit a pull request and/or briefly describe your proposed solution ## System information *Please provide details of your operating system and R version* ## Additional context *Add any other context about the problem here*