@CrayzeAnimation I’m afraid that the Vector tools are a work in progress right now. It’s not safe to use them in any version. From what you’re describing there was a bug related to the loss of thickness that was fixed in the latest versions of Pencil2D however it only applied to files that were created with really old files where the user lost the thickness.
Sadly I can only ask you to upload your file to a file sharing service like google drive, dropbox or mega.nz and share the link here so a developer can take a look to see if it’s possible to help recover the pressure data.
Truth be told, right now I’m recommending anyone that wants to “clean-up” their animation with vectors to use Pencil2D for the rough animation stage (bitmap), and use Synfig (http://synfig.org) for the clean up stage (vector).