Q: Visa stamping after switching back to previous company

I am confused about a prospective visa stamping that I plan to go for this year. I was with my company for 7 years and they had filed my Labor application(I-140 approved). They filed for my H1 extension which is valid till 2021. Last year, I switched jobs and had an approved H1 transfer. However, the new job did not work out and I was back to my old job again. They said that they hadn't cancelled by H1, so I was able to join without much delay(There was a 2-3 week gap in between to complete the HR procedures). I was wondering f this will be an issue during stamping. Would I need to take both my I797 forms for my interview and would I need any documentation from either companies explaining my situation? 

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