Adobe Acrobat exits fullscreen mode when switching between tabs or documents

I am facing the same issue, and my productivity has reduced because of this very annoying issue. I called up the customer service and they just blamed the MacOS and asked me to contact Apple. I did that too to cover up all bases, and there was nothing wrong with the Mac, and the source of the problem with Acrobat Adbobe is itself!! 
I have started looking for alternatives to Adobe! 

Hi @alfrednrejaj, 

Thanks for reaching out. 
While in Full Screen, if you switch between tabs, Acrobat will exit Full Screen. I think this is because Acrobat has app and file preferences for file preview. Also, I am checking internally to see if there is anything else to it. https://adobe.ly/3Wim3EG;