Footer in Chat Bot for google chat behaving weirdly

[Vishnu dut]

I have a chatbot built using app script for google chat. It has a number of dialog boxes. Everything was fine until this morning. The footer's fixed position is changed and gets dragged if there's white empty space above it. I will post the image for better understanding. 

This has happened in all the dialog boxes. There was no change that was made in the code.  Any one have faced this issue before ? Any help will be appreciated. 

Thanks