Hi Jonas, thanks as ever for your helpful advice.
You're totally right - this looks like they have the same UUIDs.
This confuses me though. Is it deliberate? Unless I misunderstand, it means that if someone gets Ecoinvent from Nexus, then they can't combine system and unit processes from the same system model (e.g. cutoff)! To me, this means that the nexus version of Ecoinvent3.5 is broken.
I don't see an option to "overwrite" when importing a zolca (e.g. in the way that there is if importing a JSON-LD). However, this is definitely not what I'd want - I'd like to see both processes (UP and LCI) next to each other, so that the appropriate one can be selected for a given product system. Surely it is not so unusual to want to use unit processes for the main parts of your product system (so that you can see the detail and also drill down a bit further in results) but then use system processes for parts of the product system that are less central (to make it computation reasonable).
Thanks for the link to the manual :) It is well written and useful - I did have a look through already. I think maybe you're referring to p7 where having a UUID the same for a given process between different database versions is desirable. However, this is quite a different situation and possibly contradicts the 2nd paragraph - maybe attempting this when constructing the zolca version was the source of the problem however?
In fact, the manual even states that the six databases can be used in combination. If they have identical UUIDs for some processes then I don't think this is always true.
Is there a way I can do a bulk change of all the UUIDs in the system process dataset (i.e. preferring that to changing the unit process one so that preferred providers aren't messed up) so that e.g. each is assigned a new random UUID or something? I realise that this would break compatibility with models created in earlier versions but that is not a concern for us.