PDF not rendering correctly

I confirm, as wrote in the release note we decided to name the new version 3.50.

We've found an issue in rendering after zoom ends for canvas rendering method (not-opengl).
After zoom the page is not refreshed until a pan movement is applied.
We will fix it with RC3.

In the meanwhile I suggest you to use the native libraries (.so) from 3.50RC2 and include in 3.13.5 framework.