PT (Lula’s party, a labour party with socialists, communists and other leftists) put out a statement by the party’s president congratulating Maduro without telling him…which really pissed Lula off, and then some of the main voices of the party dissented from the official view, many of Lula’s ministers condemned Maduro and asked for the official release of the disaggregate vote tally certificates.
So now the party is split in two either because it makes the party look bad (the neoliberals, the conservatives and the far right are having a field day with this) and because many agree that it goes against all they hold dear (e.g. Dilma, the former president, was tortured in prison by the former right-wing military dictatorship)
Lula doesn’t want to break ties, because he wants leverage to prevent Maduro from trying to invade Guyana.