No need to nuke the whole repo.
The recent updates from Apple are providing the .dist files in a compressed format.
The latest reposado code includes a new curl option to handle that, but if you have already synced with the previous code you need to do a little cleanup.
1) Update the reposado code to the latest from the repo
2) Identify the Invalid XML files from the repo_sync log and remove those files from the paths they are at. You only need to remove the .dist files, not the whole folder.
3) Run repo_sync again with the new code.
That will clean up the errors you're seeing.