It seems to happen reproducibly by looking at build.golang.org, though it's less noticeable because the builder is marked as having a known issue #52150. Still, the builder is currently in the default TryBot set, so this needs attention.
Same as CL 418475, but for Unified IR.
TryBot-Result: Gopher Robot <email@example.com>
Reviewed-by: Matthew Dempsky <firstname.lastname@example.org>
Run-TryBot: Cuong Manh Le <email@example.com>
Reviewed-by: Than McIntosh <firstname.lastname@example.org>