I'm getting bogus-seeming errors in the PatchChanges stage when I run "cros tryjob" with -p flags.

I'm running "cros tryjob --hwtest -p chromiumos/third_party/autotest:tast_lab -p chromiumos/overlays/chromiumos-overlay:tast_autotest lumpy-release-tryjob". The chromiumos-overlay change, which is uploaded at https://crrev.com/c/896262, is a single commit on top of upstream. It renames chromeos-base/autotest-all/autotest-all-0.0.1-r41.ebuild to chromeos-base/autotest-all/autotest-all-0.0.1-r42.ebuild.

https://chromium.googlesource.com/chromiumos/overlays/chromiumos-overlay/+/master/chromeos-base/autotest-all/ shows that upstream currently has a autotest-all-0.0.1-r41.ebuild symlink pointing at autotest-all-0.0.1.ebuild.

My builds, e.g. http://uberchromegw/i/chromiumos.tryserver/builders/release/builds/19620, are failing in PatchChanges with an error like this:

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17:37:01: INFO: Attempting to apply change chromiumos/overlays/chromiumos-overlay:tast_autotest:0f764b8a:"chromiumos-overlay: Add autotest-server-tests-tast package."
17:37:01: INFO: Rewinding transaction: failed changes: chromiumos/overlays/chromiumos-overlay:tast_autotest:0f764b8a:"chromiumos-overlay: Add autotest-server-tests-tast package." .
Traceback (most recent call last):
  File "/b/c/cbuild/repository/chromite/cbuildbot/patch_series.py", line 941, in _Transaction
    yield
  File "/b/c/cbuild/repository/chromite/cbuildbot/patch_series.py", line 886, in Apply
    self._ApplyChanges(inducing_change, transaction_changes)
  File "/b/c/cbuild/repository/chromite/cbuildbot/patch_series.py", line 110, in f
    return functor(self, parent, *args, **kwargs)
  File "/b/c/cbuild/repository/chromite/cbuildbot/patch_series.py", line 976, in _ApplyChanges
    self.ApplyChange(change)
  File "/b/c/cbuild/repository/chromite/cbuildbot/stages/sync_stages.py", line 185, in ApplyChange
    return patch_series.PatchSeries.ApplyChange(self, change)
  File "/b/c/cbuild/repository/chromite/cbuildbot/patch_series.py", line 306, in f
    return functor(self, *args, **kwargs)
  File "/b/c/cbuild/repository/chromite/cbuildbot/patch_series.py", line 342, in ApplyChange
    return change.ApplyAgainstManifest(self.manifest, trivial=False)
  File "/b/c/cbuild/repository/chromite/lib/patch.py", line 1293, in ApplyAgainstManifest
    trivial=trivial)
  File "/b/c/cbuild/repository/chromite/lib/patch.py", line 1177, in Apply
    self._FindEbuildConflicts(git_repo, upstream, inflight=inflight)
  File "/b/c/cbuild/repository/chromite/lib/patch.py", line 1413, in _FindEbuildConflicts
    raise EbuildConflict(self, inflight=inflight, ebuilds=conflicts)
EbuildConflict: chromiumos/overlays/chromiumos-overlay:tast_autotest:0f764b8a:"chromiumos-overlay: Add autotest-server-tests-tast package." deletes an ebuild that is not present anymore. For this reason, we refuse to submit your change.
When you rebase your change, please take into account that the following ebuilds have been uprevved or deleted:
- chromeos-base/autotest-all/autotest-all-0.0.1-r41.ebuild
17:37:01: INFO: Failed applying transaction for chromiumos/overlays/chromiumos-overlay:tast_autotest:0f764b8a:"chromiumos-overlay: Add autotest-server-tests-tast package.": chromiumos/overlays/chromiumos-overlay:tast_autotest:0f764b8a:"chromiumos-overlay: Add autotest-server-tests-tast package." deletes an ebuild that is not present anymore. For this reason, we refuse to submit your change.
When you rebase your change, please take into account that the following ebuilds have been uprevved or deleted:
- chromeos-base/autotest-all/autotest-all-0.0.1-r41.ebuild
17:37:01: ERROR: Failed applying patches: chromiumos/overlays/chromiumos-overlay:tast_autotest:0f764b8a:"chromiumos-overlay: Add autotest-server-tests-tast package." deletes an ebuild that is not present anymore. For this reason, we refuse to submit your change.
When you rebase your change, please take into account that the following ebuilds have been uprevved or deleted:
- chromeos-base/autotest-all/autotest-all-0.0.1-r41.ebuild
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This doesn't make sense to me, as autotest-all-0.0.1-r41.ebuild still exists.

When I submit a tryjob with the same two changes, but using "-g 896262 -g 894730" instead of the -p flags, PatchChanges succeeds: http://uberchromegw/i/chromiumos.tryserver/builders/release/builds/19619