Cannot open pdf document after installing April 2019 CU

Installed April 2019 CU last night(The updates was SharePoint 2013) and next day users are not able to open pdf documents. They get the following warning and when click on on OK, they will get the same warning for the second time and nothing happens:

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Note that it is affecting IE 11 (32-bit). However, it works fine with Microsoft Edge, FireFox, Opera, and Chrome.