The latest 0.5.3 release of the inputstream helper addon contains a temporary fix which will download a working widevine version - see Release v0.5.3 · emilsvennesson/script.module.inputstreamhelper · GitHub
It looks like it's available in kodi 19/Matrix addon repo, but not 18/Leia. So on LE10beta an addon update should do the trick, on LE9.2 you have to download and install the zip manually. Then kick off a widevine download/update in the inputstream helper addon.
See also these issues for more background info
Latest Widevine 4.10.2252.0 fails to load · Issue #678 · xbmc/inputstream.adaptive · GitHub
so long,
Hias