Always true condition changes result

Hello guys. I have the following simple query:

from(bucket:"bots-requests-stats")
    |> range(start: -1h)  
    |> group(columns: ["_field"]) 
    |> sum()

It’s ok. But if I add a simple and always true condition:

from(bucket:"bots-requests-stats")
  |> range(start: -1h)
  |> filter(fn:(r) => "All" == "All")
  |> group(columns: ["_field"]) 
  |> sum()

Then query’s result table have a different columns set. Here is both queries results:

Why does it happen and how do I avoid this? Thank in advance

Hello @Alexander_Kochagov,
Can you please export some data and share it with me?
I just did a test with some dummy data and the results were consistent for me:

mymeas,mytag=foo myfield=1
mymeas,mytag=foo myfield=2
mymeas,mytag=foo myfield2=1
mymeas,mytag=foo myfield2=2
from(bucket: "test")
  |> range(start: v.timeRangeStart, stop: v.timeRangeStop)
  |> filter(fn: (r) => r["_measurement"] == "mymeas")
  |> group(columns: ["_field"]) 
  |> sum()
  |> yield(name: "mean")

and

from(bucket: "test")
  |> range(start: v.timeRangeStart, stop: v.timeRangeStop)
  |> group(columns: ["_field"]) 
  |> sum()
  |> yield(name: "mean")