🚨 Error: Null promise in layoutCallback

Details
---
**Error report:** [link](http://go/ampe/CPqztOO6vqmUWw)
**First seen:** Dec 26, 2020
**Frequency:** ~ 21,972/day

Stacktrace
---

Error: Null promise in layoutCallback

    at message (src/core/error/index.js:43:22)

    at src/utils/log.js:295:50

    at this (src/utils/log.js:271:43)

    at TAG (amp-a4a/0.1/amp-a4a.js:1343:20)

    at attemptToRenderCreative (amp-a4a/0.1/amp-a4a.js:1323:16)

    at idleDeadline (src/chunk.js:190:15)

    at idleDeadline (src/chunk.js:409:17)

    at src/chunk.js:322:41

Notes
---
`@rcebulko` modified `src/core/error/index.js:32-50` in [#33881](https://github.com/ampproject/amphtml/pull/33881) (Apr 16, 2021)
`@rcebulko` modified `src/utils/log.js:295-295` in [#35621](https://github.com/ampproject/amphtml/pull/35621) (Aug 11, 2021)
`@rcebulko` modified `src/utils/log.js:271-271` in [#35621](https://github.com/ampproject/amphtml/pull/35621) (Aug 11, 2021)
`William Chou` modified `src/chunk.js:189-198` in [#6967](https://github.com/ampproject/amphtml/pull/6967) (Jan 27, 2017)
`@cramforce` modified `src/chunk.js:409-410` in [#23750](https://github.com/ampproject/amphtml/pull/23750) (Aug 7, 2019)
`William Chou` modified `src/chunk.js:322-322` in [#6967](https://github.com/ampproject/amphtml/pull/6967) (Jan 27, 2017)

**Seen in:**
- 02-14 Beta (2035+1)
- 02-14 Experimental (2035+1)
- 02-23 Control (0359+1)
- 02-23 Nightly-Control (0359+1)
- 02-23 Stable (0359+1)
- 03-04 Nightly (1950)
- +1 more

/cc @ampproject/release-on-duty