Hi @onmrc - another update and questions here :
Took a source code approach to this. Looks like the error is related to a global variable "$wp_locale" which has something to do with translation, not sure exactly what it does.
But the logs suggest "$wp_locale" is null at the time of the error. I can't tell if this is exactly related to the error the pub is having but it is fatal.
We're also looking for a sort of step back briefly, because we're a bit confused as to what exactly is going on with the error at this point.
Originally we were working on a blank white screen during installation, and now it seems to be different (looks like the publisher was able to install the plugin fine, just not the update after).
Would it be possible to have another short video taken showing the issues now, or even just screengrabs with descriptions of specifically what process are being followed that we're still seeing issues for.
Further, would the publisher be open to our tech team messing around with the wpml settings here and there, in order to reproduce?
Looking forward to hearing from you soon!