One of the leading contenders to succeed Angela Merkel is facing an embarrassing debacle over his flagship coronavirus testing policy.
Markus Söder, the regional prime minister of Bavaria, has seen his popularity soar over his handling of the crisis and is now openly talked of as the frontrunner to take over from Mrs Merkel.
But on Thursday he was fighting to contain the fallout after it emerged that some 44,000 people had not received their results more than a week after taking part in a new Bavarian testing scheme.
Even more damaging, it emerged than 900 of those who had not received their results had tested positive, raising fears they could have passed on the infection unknowingly.
“This is very, very frustrating,” Mr Söder said. “It needs to be fixed immediately and it must not happen again.”
The Bavarian leader was privately said to be livid after he was forced to cancel a planned trip to the German north coast in order to sort out the mess.
The trip to Schleswig-Holstein, which would have included a walk across North Sea mudflats, was part of a bid to raise his national profile as he attempts to position himself as Mrs Merkel’s successor in waiting.
As recently as Monday, Mr Söder was boasting that Bavaria was the only region in Germany to offer free coronavirus tests for travellers at train stations and on motorways.
Free tests are available at airports across the country, where they are compulsory for those arriving from countries deemed high-risk and optional for other international passengers.
But Bavaria has also made free tests available at the main railway stations in Munich and Nuremberg and at three motorway rest areas close to the Austrian border.
In a taunt to his rivals, Mr Söder boasted the tests were available to people from anywhere in Germany and called on other German states to follow Bavaria's lead.
But it has since emerged that the severely delayed results are all from the railway and motorway testing stations. There are unconfirmed reports the problem was caused by volunteers filling in the paperwork with pencil, which could not be machine-read.
The Bavarian Red Cross reacted angrily to attempts by regional officials to lay the blame at its door. “It is regrettable that the hard work at extremely short notice by volunteers from all the Bavarian aid organisations is being put in a bad light,” the organisation said.
For Mr Söder, who has profited as the early frontrunner to succeed Mrs Merkel, Armin Laschet, stumbled over his handling of the coronavirus crisis, it is a setback.
But while it will dent his image, it is unlikely to do lasting harm to his chances.