Following up on Widevine cdm 13816.64.0 - #9 by nfm886 .
I think this issue is not resolved, I still have it on the latest kodi 18.9 on coreelec 9.2.7. reverting to previous widevine works for the Netflix plugin but the new one does not.
There is a great bug for LibreElec that lays out the issue and there is fix available too.
Can a developer take a look and add it to CoreElec?
According to the post, it may break in a week otherwise, depending on actions from Google:
I’m using 0.5.3 of inputstream helper.
Note that when you reinstall widevine, it only loads after reboot.