Let's be un-coy then: Brexit has been a mess.

Delving further, Collins is a US firm, though with lots of sites in Europe, but the company they acquired (well, Rockwell Collins did before they became Collins), was B/E Aerospace, whose UK main location was in Leighton Buzzard, Bedfordshire. Production takes places here too, and as with a lot of other companies building things using EEE components, there's a significant cross-borders trade since air (and space) graded components aren't commonplace. And what used to take a day to be sent from, say, the Netherlands now takes three.

As an example of the sort of issues Collins is likely to face, in a previous job I worked on building, testing and qualifying an onboard computer that is now happily ticking along onboard an ESA mission. For our sins, that computer was to be built in the SE of England, then sent to Belgium for assembly, not before going to Germany for heat, vacuum & radiation testing. A lot of the 1,000+ components came from other European nations. Before 2019 there was no problem; after 2019, we were delayed 4 months just due to the hurdles of clearing customs.

To the risk of being coy, this isn't only the one issue. It's a combination of problems: availability of planes, availability of materials, availability of space in which to do the changes.