My brother is having a similar problem with the Italian threaded fixed cup on his Guerciotti.
He said the cup started unscrewing itself off the BB shell towards the end of two recent rides.
He said he thoroughly cleaned the threads of the BB shell and fixed cup and screwed it on as tight as possible with the proper tools, but the problem persists happening again in the next ride he took.
I suspect the bearings put enough rolling stress on the fixed cup to unscrew it when he pedaled.
would Locktite be the right thing to use to keep the fixed cup from unscrewing again??
Should he use blue or the stronger, red Locktite?