No, this isn't FUD. AZ wasn't lying. Yes, it's true that the EU signed one particular contract one day before the UK on August 27. However, the UK had a binding contract with AZ since May already.
"However, the key lies in an earlier agreement that AstraZeneca made back in May with the U.K., which was a binding deal establishing “the development of a dedicated supply chain for the U.K.,” an AstraZeneca spokesperson said."
The origin of the UKs priority access to the AZ vaccine was due to their early funding of the Oxford vaccine on condition of 1st priority. This was before AZ even got involved. In fact the UK govt had such deep involvement that they were able to veto a deal between Oxford and Merck to manufacture and distribute the vaccine over fears that it would allow Trump to block their priority access through export controls (as Merck would manufacture in the US) so the UK make Oxford partner with AZ. AZ inherited that pre-existing deal between Oxford and the UK govt.
Nobody is lying, the redacted agreements do indeed show that the UK agreement is dated to a day after the EU agreement but that says nothing about when money changed hands or prior deals or commitments. You get a 3 month difference between the UK and the EU because the UK had an agreement with AstraZeneca all the way back on the 17th of May (note: June -> Aug is not 3 months, that's sloppy reporting from your linked website) as can be seen here: https://www.gov.uk/government/news/funding-and-manufacturing...
It should be noted at this point that France, Germany, Italy, and the Netherlands, had jointly negotiated a deal with AZ in June but my understanding is that after an EU27 vote the EC took over negotiations and you get the final (and first for the EU) deal in August.
Why the redacted UK agreement is dated 28th of August is anybodies guess but some things should be made clear, firstly that the UK started funding AZ in May and not late August, secondly that they did this a month before other EU countries had reached an agreement with AZ, and finally that the EC getting involved added a further 2 months to the negotiation.
"However, the key lies in an earlier agreement that AstraZeneca made back in May with the U.K., which was a binding deal establishing “the development of a dedicated supply chain for the U.K.,” an AstraZeneca spokesperson said."
This quote is from this article: https://www.politico.eu/article/the-key-differences-between-...