Freeze/slowness displaying a PDF in WebBrowser control (via MFC or WinForms)

Hello, I'm having problems (freeze/slowness) by displaying a pdf in Ms IE WebBrowser control using the Acrobat Reader version 2018.009.20050; for instance, the page down/up is very slow.

The problem happens in an MFC application as well in C# WinForms when one of the parent windows of the web browser control has the Ms Windows extended style WS_EX_COMPOSITED (I've working samples if needed - both MFC and WinForms, sources and/or binaries).

When this style exists, I can observe that the AcroRd32.exe process has high CPU (~70%) and through Ms Spy++ I can see that Ms Windows paint-related messages don't stop to be generated, for instance, to the reader top toolbar; in this toolbar, it is also observed an unexpected horizontal line in the middle and at all length of the toolbar, and sometimes it generates flickering which matches the "repaint" that is being consecutively made.

In my application (MFC), and not in the samples that I've made to reproduce the issue, I had to tweak it by using the Ms Windows styles WS_CLIPCHILDREN and WS_CLIPSIBLINGS in one of the WebBrowser control parent windows, because it was freezing completely my application.

I've no idea if with older versions of the PDF reader this problem happened, or from which version the problem should start to happen, but only in the last year I've started to receive complains from my customers.

Is this problem known and there is a fix to it?