Correct, though keep mind that this was explicitly demanded for this program: https://www.bmbf.de/foerderungen/bekanntmachung-3035.html chapter 4, second bullet point. That doesn't mean they don't get reinbursed for phases 1-3. Of course I don't know for certain, I do have past experience with federal funding in Germany, though.
Considering that the company has a history of funding from this source ("BioNTech is already an old friend in our research funding. We - the BMBF - have been promoting this company since it was founded in 2007") https://www.bmbf.de/de/deutschland-kann-innovation-13125.htm... my interpretation is that this was a calculated advance payment.
Considering that the company has a history of funding from this source ("BioNTech is already an old friend in our research funding. We - the BMBF - have been promoting this company since it was founded in 2007") https://www.bmbf.de/de/deutschland-kann-innovation-13125.htm... my interpretation is that this was a calculated advance payment.