Hi Leigh thank you for taking the time to post in Lucid Community! We are currently aware a bug some users are experiencing where dashed lines and shapes are not exporting correctly. I've added this to our report with our development team.
I was able to replicate the issue on my document and recognize that this issue may hinder your workflow. As a workaround I recommend halting the use of the dashed lines/shapes temporarily and using the solid and dotted lines (The first option and last three options in the Line Style Menu). While using these two types of styles I was able to produce accurate PDF JPEG and PNG exports. I have attached a screenshot for reference as well of which ones worked for me.
If you are still seeing issues with exports using the dotted and solid lines please reach out to our support team directly using this form and one of us will assist as soon as possible!
Stay tuned on this thread for future updates!