Octopus version 3.12.5
We have a developer who is trying to edit a variable set, but he is unable to change values or scopes, and when he tries to add a variable, he gets an error that the missing permission is EnvironmentEdit.
I am currently operating under the assumption that this is a bug. I have verified that his groups have the VariableSet View/Edit/etc. permissions, but when I look at the effective permissions, there are none for any of the Variable Sets.
Hi Bob,
Thanks for getting in touch! Currently in Octopus you do require the EnvironmentEdit permission to edit library variable sets. This was done to amend a permissions issue in a previous version of Octopus. However, we realize that is has caused a lot of confusion and does not make too much sense for a user’s perspective.
We are in the final stages of fixing this and removing the requirement for the EnvionrmentEdit role to edit the library variable sets. The fix will hopefully be out within the next few releases. Below is a link to the GitHub issue for this.
Let me know if you have any further questions here. 
Best regards,
Daniel