Widevine stops working after Chrome 62 upgrade

I haven't investigated this myself yet, but various users reported that Widevine stopped working for them after upgrading from Chrome 61.0.3163.100 to 62.0.3202.62.

Situation on Archlinux:

• Chromium: has /usr/lib/chromium/libwidevinecdmadapter.so, updated to 62
• qt5-webengine-widevine (AUR): has /usr/lib/qt/plugins/ppapi/libwidevinecdm.so and /usr/lib/qt/plugins/ppapi/libwidevinecdmadapter.so, still at 61
• chromium-widevine (AUR): has /usr/lib/chromium/libwidevinecdm.so, at 1.4.8.1008 which I think corresponds to 61

Situation on Gentoo:

• www-plugins/chrome-binary-plugins: has /usr/lib64/chromium/libwidevinecdm.so and /usr/lib64/chromium/libwidevinecdmadapter.so plus symlinks with chromium-browser, updated to 62

No matter how/if this gets fixed, I think QtWebEngine should probably prefer the /usr/lib/qt/plugins/ppapi/ path over Chromium's so an older version can be dropped in easily in situations like this?