Thanks for flagging this — that error message strongly suggests a version mismatch between Prefect and the Modal integration. What’s likely happening - The Modal worker/plugin is calling an internal Prefect deprecation utility with an old call signature. In Prefect 3.x, some deprecation utilities moved/changed signatures, so older prefect-modal builds can break with “deprecation_warning() takes 2 positional arguments but 3 were given” during submit-to-infrastructure. - I couldn’t find an existing issue that matches this exact error, which further points to a local compatibility problem rather than a known platform outage. What I recommend 1) Share versions (so we can confirm compatibility):

prefect version
python -c "import prefect, sys; print('prefect:', prefect.__version__); \
           import importlib; m = importlib.import_module('prefect_modal'); \
           print('prefect-modal:', getattr(m, '__version__', 'unknown')); \
           import modal; print('modal:', getattr(modal, '__version__', 'unknown'))"

2) Upgrade Prefect and prefect-modal together, then rebuild/redeploy your Modal image/app used by the work pool:

pip install -U prefect prefect-modal modal
# or with uv
uv pip install -U prefect prefect-modal modal

- If your Modal push worker builds an image, make sure that image includes the updated packages and gets rebuilt/pushed before the next run. 3) Re-run your deployment. If the error persists, please grab the full traceback from the worker logs (set

PREFECT_LOGGING_LEVEL=DEBUG

if possible) and share it here. 4) Temporary workaround if you need to unblock immediately: pin Prefect back to the last known-good version used by your previously working runs and rebuild your Modal image with that exact version. Then we can work forward from there. Useful references - Modal guide: Run on Modal (Prefect 3.x) - Modal provisioner API (3.x): Modal provisioner API - Plugin repo (to check releases/issues): Prefect Modal integration If you can share: - Prefect, prefect-modal, and modal versions - A snippet of your work pool type and any relevant

prefect.yaml

bits for the Modal build/push - The full stack trace around the error …I’ll dig in and help you get this resolved quickly.

Thanks for the extra detail — that’s really helpful. Given: - It happens on all Modal push runs - You’ve pinned Prefect to 3.1 and 3.4 with no change - There are no Modal app logs (so it fails before Modal code runs) - Prefect UI shows only the single “submit to infrastructure” error This points to a server-side error in the Modal provisioner for push pools (likely a deprecation utility signature mismatch introduced recently). Pinning your local Prefect version won’t impact the submit step for push pools because that submit happens in the provisioner/worker environment managed by Prefect. To move this forward quickly: Immediate options to get unstuck - Switch the deployment temporarily to another work pool type (e.g., Process or Docker) so your schedules can continue while we investigate Modal push. - Or, if feasible, run your flows via a pull-based worker you control (local or infra you manage) until Modal push is fixed. Helpful diagnostics (please share) - Workspace name (or slug), region, and the Modal work pool name - One or more recent flow run IDs showing this error and approximate timestamps - Output of:

prefect work-pool inspect "<your-modal-push-pool>"

If you can run this, it’ll confirm the pool type and configuration we’re troubleshooting. Optional: try to re-provision the pool (may surface more error context)

prefect work-pool provision-infrastructure "<your-modal-push-pool>"

What I suspect - A regression in the Modal provisioner’s deprecation warning call (a signature change) on the server/plugin side. That would explain why your runs started failing “recently” and why local pinning hasn’t helped. Next steps - If you can share the details above, I’ll escalate to our engineering team right away. This looks like something we need to fix on our side. - If you prefer, you can also open a ticket with those details so we can correlate logs and timelines from the backend. Refs - Modal guide (3.x): Run on Modal (Prefect 3.x) - Modal provisioner API docs: Modal provisioner API I know this is frustrating without visibility into the plugin internals — thank you for your patience. If you share your workspace/pool/run info here (or DM), I’ll get this in front of the team and follow up with status.