Hi @shang l thank you for posting in the community! It looks like you have identified a bug where lines containing text will appear bolded in a PDF export. I have reported this to our development team. 

We rigorously prioritise what to work on based on the extent and criticality of the issue -- because of this it is not likely that this issue will be resolved quickly. I am very sorry for the inconvenience.

As a workaround in the meantime I recommend adding text to your lines using a text box shape. I understand this is an extra step however it should help you continue your work in the meantime as the exported file will not have the bolded lines. 

to clarify this bug happens regardless of whether there is text on the line

https://ibb.co/47czWpB

Hi @shang l thanks for following up with that information! After some additional investigation on my end it appears that the bug happens when text (or even just a space making it appear like there is no text) is added to the line.

If possible could you please try recreating the line without adding any text (or spaces) to it and confirm if you still see the same behaviour? Thank you!

deleting the text has definitely made a change but as you can see there still remains some line weight inconsistency

https://ibb.co/vV8R5Bj

Hi @shang l thank you for confirming that and apologies for the trouble! In the meantime it might be helpful to use the text box shape workaround to prevent bolded lines in the export file. Alternatively it seems like the line weight does not occur when exporting the document as an image file. 

I will add these details to the bug report and will update this thread once I have more information. Feel free to let us know if you have any questions in the meantime!