You are correct, foreign office policy hasn't changed and so while we are leaving the EU, EU nationals no longer pass security clearance.
Is it really that hard to follow?
Just to be clear, this is what Sara said before the media picked up on it
'UK govt previously sought work& advice from best experts. Just told I & many colleagues no longer qualify as not UKcitizens'
'1/Thanks for all reactions.I stand by fact there is new tone in UKgovt business& I had specific rejection re advisory work as not UK citizen'
'2/But am proud to be part of outstanding experts @lse & @ukandeu who value diversity, integrity in addition to professional expertise.'