Hi all,
I’m hitting a strange scheduler issue that I can’t explain. Bubble support has been engaged in parallel, but I’d love a second opinion from the community.
**Note**: I’ve reviewed similar past threads (“Scheduled API Workflows down?” from 2016 — resolved as latency; “Schedule API workflow on list not populating in log” from 2017 — resolved as empty Search list). **My case is different**: the Search successfully returns matched users, the Schedule action confirms scheduling for those users, but the target workflow itself never executes.
## TL;DR
“Schedule API Workflow on a list” logs **“Finished running action”** with successful scheduling for matched users, but the **target workflow never logs “Started running workflow”** and never executes. Same workflow runs perfectly when called directly via curl.
## Setup
I have a Recurring Event chain that sends morning LINE push notifications:
```
recur_morning_gym_push_all (Recurring Event, daily 7:00 AM JST)
└─ Step 1: Schedule API Workflow “send_morning_gym_push_batch” on a list
↓ (this is where it breaks)
send_morning_gym_push_batch
├─ Step 1: Create a new WebhookDebug (debug marker)
└─ Step 2: Schedule API Workflow "send_daily_habit_push" on a list
↓
send_daily_habit_push
└─ Sends LINE push via API connector
```
## Symptom
For ~18 days (since around May 11, 2026), the chain breaks at the **first hop**:
Server logs at 7:00 AM:
- 
`recur_morning_gym_push_all` — Started / Finished (WUs: 1.50)
- `Schedule API Workflow send_morning_gym_push_batch on a list` — Running action / Finished running action (WUs: 0.90), with valid Scheduled date (current timestamp, not in the past)
- 
`send_morning_gym_push_batch` — **NO “Started running workflow” log. Ever.**
- No WebhookDebug record created (which Step 1 would write).
- No LINE push delivered.
The “Schedule on a list” action reports success, but the scheduled tasks vanish.
## What I’ve ruled out
1. **Scheduler not paused** — Scheduler tab shows “Pause tasks” button (not “Resume”).
2. **WU not exhausted** — ~4,700 WUs used this month on Starter plan.
3. **Search not empty** — Logs confirm 2 users matched and 2 schedules were created.
4. **Target workflow has no blocking conditions** — `send_morning_gym_push_batch` has no Only when, no Terminate steps. Both Step 1 and Step 2 have empty Only when fields.
5. **Scheduled date is valid** — Confirmed Scheduled date is current timestamp, not in the past.
6. **Workflow itself works fine when called directly** — Direct curl POST to the workflow endpoint executes the full chain perfectly: WebhookDebug created, downstream scheduled, LINE push delivered. Every. Single. Time.
## What I’ve tried
- Simplified the chain by changing Step 1 of recur to schedule `send_daily_habit_push` directly (bypassing the middle batch). Same result: scheduled but never executes.
- Tested with only 1 user in the Search results — same issue.
- Verified Search constraints (`line_user_id isn’t empty`, `gym_days isn’t empty`, `registration_status = “friend”`) all match my user correctly.
- Tried to roll back via Save Points, but the branch was created less than 14 days ago, so I cannot go back to a known-working state.
## Key contrast
| Invocation method | Result |
|—|—|
| Recurring Event → Schedule on a list → target | Schedule “Finished”, target never starts |
| Direct curl to target workflow | Works perfectly, every time |
This isolates the failure to the **scheduled task pickup/execution layer**, not the workflow logic.
## Question
Has anyone seen scheduled tasks (created via “Schedule API Workflow on a list”) silently fail to execute while the Schedule action itself reports success?
- Is there a way to inspect the internal scheduler queue beyond the Scheduler tab?
- Could there be a stuck/poisoned scheduler queue specific to one app?
- Has anyone had Bubble support resolve a similar issue from the backend?
App is on Starter plan, branch is Main (Development version).
Any insight appreciated. I’ll update this thread if Bubble support comes back with anything.
Thanks
