No results with `join.inner()` on generated data

Fluxlang
1

Hello :wave:
I’m quite new to Flux lang and I’m having trouble testing the join.inner() function.

I tested it by joining data coming from real buckets or generated with array.from() function and all went ok.

Then I test it with data generated with generate.from() function by I can’t get any result back. Here the snippet failing to return expected result :

// Generate data
t1 =
    generate.from(
        count: 4,
        fn: (n) => n + 1,
        start: 2024-02-14T13:21:56Z,
        stop: 2024-02-14T13:22:36Z,
    )
        |> set(key: "tag", value: "foo")
        |> group(columns: ["_time"])
        |> yield(name: "t1")

t2 =
    generate.from(
        count: 4,
        fn: (n) => n + 2,
        start: 2024-02-14T13:21:56Z,
        stop: 2024-02-14T13:22:36Z,
    )
        |> set(key: "tag", value: "foo")
        |> group(columns: ["_time"])
        |> yield(name: "t2")

result = join.inner(
    left: t1,
    right: t2,
    on: (l, r) => l._time == r._time,
    as: (l, r) => ({l with rightValue: r._value}),
)
    |> yield(name: "RESULT")

Am I missing something? If I use the plain join() function everything works fine.