Well, they probably have some kind of tile "lint", need to precompute a bunch of routing data (depending on what their actual algorithm is), sync all their rend

Well, they probably have some kind of tile "lint", need to precompute a bunch of routing data (depending on what their actual algorithm is), sync all their rendering/prerendering pipelines at a common revision, propagate outputs to cache servers, etc. So it can't easily be done at every change, unless they have a design where small incremental deltas are explicitly supported by all their services. It is a time- and resource-intensive process. Still, three months sounds like a lot.