This problem surfaced last night. Got to Diamond City after 60+ hours gametime (been doing side quests). Went and started the Unlikely Valentine quest. Now when I go to Vault 114 and free Valentine any saves before (anywhere near Diamond City) and any saves made after rescuing Valentine get me a one way ticket to the Desktop. I'm reluctant to progress further as I have no idea if it will generate a working save. I've had the usual bugs like invisible pip-boy / weapons etc and a reload of a save fixes them.

Any ideas on how to progress the game?