Adobe DC Reader version 19.008.20080 causing IE to crash in Windows 2016 server Citrix XenApp environment

Hi there, within the last few weeks post the automatic update of Adobe DC Reader in our Citrix farm, we have had many users complain that IE crashes when trying to view a PDF file in the browser. If we disable the DC Reader add-on in IE, then the file is downloaded and opened in DC Reader.

We are running a Citrix Xenapp 7.5 farm, on Windows 2016 server - shared desktop environment, so approx. 10 users per server.

We only noticed this within the last few weeks, roughly two weeks since DC Reader updated automatically.

What we have observed is that if we delete the following registry key "HKCU\SOFTWARE\Adobe\Acrobat Reader\DC\AcroApp\cRegistered\c11", and then browse the internet via IE to view a PDF within the browser it works. But as soon as you open DC reader in the same users's session the c11 key is re-added and then viewing PDF in IE crashes again.

Can someone please help, as we don't know what has changed in our environment. It is pretty standard and we haven't made any changes to the software on our environment, no GPO changes, so struggling to resolve this issue for our user base.

Thanks in advance,

Alex