Another source noted that Hitler had to hide von Bock’s resignation for several months. The “failure at Voronezh” is so obscure phenomenon that von Bock’s resignation would raise a question for Hitler himself. For what?
https://b-ok.cc/book/3386571/6f8818
After Hitler's departure, Bock momentarily hesitated about Voronezh. But the daring of his panzers soon decided the issue for him. On July 4, forward elements of the Fourth Panzer Army's 24th Panzer Division reached the Don, found a bridge that was still intact, and, daringly mixing in with retreating Russian units, roared on toward Voronezh. When Bock learned that his tanks were a few miles from Voronezh, he gave the order for them to finish the deed.
Bock was right: The operation netted only around 50,000 prisoners. But in Hitler's eyes. Bock had protested too much and delayed too long. On July 13, the Fiihrer changed plans again. Convinced that large numbers of Russians were concentrated along the lower reaches of the Don, he abandoned the scheduled drive by all forces eastward toward Stalingrad and prepared a major encirclement by List's Army Group A around Rostov, 125 miles south of Millerovo. To spring the trap, he stripped Bock's Army Group B of the Fourth Panzer Army and gave it to List, leaving the Sixth Army as the only German force available on the northern flank. Then, virtually in the same breath, having developed "a distinct antipathy for Bock, " as an aide later put it, he stripped Bock of his command. Bock was ordered to turn over Army Group B to his commander on the northern wing, Maximilian von Weichs—again, a change ostensibly "for reasons of health. " Such was the field marshal's prestige, however, that the Fiihrer ordered the shift in command to take place in the strictest secrecy. For months, stories and photographs of Bock appeared in the government controlled press as if he were still in command of the southern front in Russia. But the seasoned veteran, with forty-five years of military service behind him, would never command troops again.