Hello @tarafield2015,
Apologies for the late reply due to the weekend. 
First of all, please allow us to mention that the issue is resolved with the new action (Generate pdf from HTML server-side ConvertortoPDFv2.0 ) and now you can use it to convert the invoice. But, please note that you do not need to use old and new actions in the same event.
Also, in order to reproduce this issue in your app, could you please send us a video recording showing the issue? As I can see we have still access to your app but we need to understand what steps we need to take to test this behavior.
Like how to create an invoice and download it. We will do our best to solve this issue but we need to understand how exactly we can reproduce it on our side.
You can use the Loom tool for video recording and share it via DM.
Thank you! Looking forward to your reply.
Best regards,
Zeroqode Support Team