See e.g. T273099: there is an "Assigned To" row in the information sidebar, but I see no Assign/Claim option in the dropdown above the comment field, and no Assigned To field in the form when editing the task.
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Description
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Noticed this in the train log triage meeting as well. I noticed on the form "owner:hidden" was set on production errors. I don't see the edit that caused that...but I changed it to "owner:visible" so now that form appears.
Very strange. Adding @mmodell for visibility.
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T240343 looks related; see https://phabricator.wikimedia.org/transactions/editengine/maniphest.task/view/46/ for changelog