I saw this on the ScienceFiction&Fantasy.SE homepage, and it made me cock my head; the link on questions that typically says "asked X minutes ago" or "modified Y minutes ago" or whatever, doesn't know what happened to this question.
Clicking into the question, it was originally asked on RPG.SE, and migrated to SFF.
There's another, similar case from much earlier; this one is missing both the "action" ("asked", "modified", etc.) and the user who performed the action:
This one was migrated from Movies&TV.SE, and asked by a user who doesn't have an SFF account to link:
Although I can't personally confirm it, one of the Mods on OpenSource.SE confirms that he sees this a lot when handling migrations on that site:
I deal with migration to and from Open Source frequently, being a moderator there, and I see this every time.