It's unclear to me whether "new apps" refers to entirely new apps (added after the announcement of changes) or also to new builds of existing apps. Apple uses "new apps" everywhere, and the only site mentioning "new and existing apps" is 9to5mac, which doesn't support this information with any sources. Does anyone know if this also applies to updates to old apps?

I can confirm the bug. The URLs look the same in the logs - that's true, but in fact they are encoded two times. This seems to be a critical problem.