hi guys,
i’m currently running into similar troubles with the latest gp-premium update. it seems to interfere somehow with the editor in wordpress (latest version). problem seems to affect all types of pages, be it with sections or without. looks like jetpack is causing a conflict here. turns out after some testing, this relates to the option “check grammar and spelling” in jetpack. once this is deactivated, pages can be edited with gp premium. maybe it helps somehow.
best
christoph