Google Doc PDF not consistently being added to email as attachment

See previous post for background info: 

https://community.zapier.com/general-questions-3/wrong-attachment-sometimes-being-sent-in-gmail-14260

I have a Zap set up that does the following steps

1. Checks for New/Updated records in an Airtable view
2. Creates a Google Doc from a template based on the info in the record
3. Emails that Google Doc out as a PDF attachment to the email address in the Airtable record (By attaching the Export Links Application/pdf link from the previous step)

Upon trying this again with a “Delay After Queue” step implemented, most of the emails sent were completely fine and attached the PDF as intended. But a random selection of records, the attachment to the email was ServiceLogin.htm, and my clients weren’t able to access the PDF.

Anyone have this happen or have a workaround for how to prevent it from happening in the future? 

I received advice to try adding in the delay step - which didn’t work. I also tried doing smaller batches (I was initially doing 200 - I’m now only doing 40 - edit: tried it with 5 and it still happened) - and the issue still happened. I saw some posts indicating that it was something timing out - is there a way to fix it? Seems like Zapier may not be the solution for me if this keeps happening.

Thanks for any advice!