Ed Sheeran says that his album date had to be rushed because Adele had already booked out all the vinyl factories. For that reason his record came out 2 months earlier than expected. He finished it in July so there would be enough time to press the vinyl.
With only 3 vinyl factories in the world, a back-up on production was created when Coldplay, Taylor Swift, Abba, and Elton John also wanted to release an album around the same time. They ultimately changed their release date as well.
Vinyl's resurgence in popularity over the past decade has caused major issues for manufacturers, and the small number of pressing plants aren't able to meet the high demand which is double what they can produce.