Machine run is inconsistently printing data from stdin

[lugoues]

Describe the bug
I am attempting to execute an admin task in an application using fly machine run in which I pass the secrets through stdin to be read by my server-side script, but fly machine run inconsistently outputs stdin data which would expose the secrets to logs.

In the Command output below there are two identical commands being run but you will notice that the first one prints out TEST=123 prior to executing the command. Also, the env is inconsistently placed (sometimes above test sometimes below` so maybe an async process?

• Operating system
  flyctl v0.3.170 linux/amd64 Commit: 7986a9f6360ff8d7b57ee1c72fa833a4193a605f BuildDate: 2025-08-12T17:58:00Z

** Paste your fly.toml
n/a using adhoc app

** Command output: **

# First Command
λ echo TEST=123 | fly machine run \
    'debian' \
    --org 'my-org' \
    --skip-dns-registration \
    --rm \
    --shell \
    --command "echo test"
Searching for image 'debian' remotely...
image found: img_wd57v5658wwk438o
Image: docker-hub-mirror.fly.io/library/debian:latest@sha256:a9114963cf3cd27fdae799d3c987758a26709515db3673ce85e2c4befd88199e
Image size: 49 MB

Success! A Machine has been successfully launched in app flyctl-interactive-shells-m8y4w6laklyj3ixrnj48ml6bb8ub85l1l-355
 Machine ID: 1859e73a130018
Connecting to fdaa:13:8297:a7b:4b3:ab81:3e7d:2... complete
TEST=123
test
machine 1859e73a130018 was found and is currently in created state, attempting to destroy...

# Second Command
λ echo TEST=123 | fly machine run \
    'debian' \
    --org 'my-org' \
    --skip-dns-registration \
    --rm \
    --shell \
    --command "echo test"
Searching for image 'debian' remotely...
image found: img_wd57v5658wwk438o
Image: docker-hub-mirror.fly.io/library/debian:latest@sha256:a9114963cf3cd27fdae799d3c987758a26709515db3673ce85e2c4befd88199e
Image size: 49 MB

Success! A Machine has been successfully launched in app flyctl-interactive-shells-m8y4w6laklyj3ixrnj48ml6bb8ub85l1l-355
 Machine ID: 7819514a5d3348
Connecting to fdaa:13:8297:a7b:4b3:2c2c:4afc:2... complete
test
machine 7819514a5d3348 was found and is currently in created state, attempting to destroy...