It can definitely be interpreted as CYA. They are following the recommendation of the Paul-Ehrlich-Institute, a federal regulatory body.

Imagine they went against this recommendation and it turns out there is indeed an issue with the vaccine. That would cause a shit storm of epic proportions. This way the "worst" that can happen is that there was a delay.

Now people could die during that delay because they weren't vaccinated, but it's much easier to sweep that under the rug as a politician, in my opinion.