See Semmler, Goebbels — the Man next to Hitler. Semmler noted on 20th November 1943:
'I noticed for the first time that Goebbels admits to his intimates his weakness in relations with Bormann. He will not allow the slightest ill feeling to arise between himself and the head of the Party Chancellery.
'How inconsistent Goebbels can be. The day before yesterday he elaborated critically on Bormann's modest intellectual capacity. He called him a "primitive GPU type [OGPU]".
Today he indicates that he is afraid of him!' And the next day Semmler remarks: 'Goebbels often feels that he has expressed himself too candidly about Bormann. At table he warned us once more not to pass on to anyone what was said there.'
On the Goebbels-Bormann struggle see also Trevor-Roper, Martin Bormann. Incidentally, it was not only towards the end of the war that Bormann attempted to undermine the Propaganda Minister's position. As early as December 1941 Semmler noted:
'Bormann especially does what he can to increase the distance between them [Hitler and Goebbels]' (Goebbels, entry for 12th December 1941).