Adobe tools

I am currently using the Adobe Reader app on both my Samsung tablet and also on my Samsung 2 in 1 Chromebook laptop. My problems are:

- The highlight function works sporadically.  It is hit or miss when I start the program as to whether it will work.  When it works it is great. I use the function fairly often.

- Secondly, the document does not always save the changes I've made (writing in text, highlighting...etc) when I exit the document.

Is there something I'm doing wrong or is there an issue with the app??

I have uninstalled and reinstalled the app several times.

I love this and would love to have more consistency.

Jim