🚨 Error: Failed to parse <script> contents. Is it valid JSON?

Details
---
**Error report:** [link](http://go/ampe/CIi6mq3UxIrWJA)
**First seen:** Nov 18, 2020
**Frequency:** ~ 11,274/day

Stacktrace
---

Error: Failed to parse  contents. Is it valid JSON?

    at Error (<a href="https://github.com/ampproject/amphtml/blob/2012050452002/src/json.js#L155">src/json.js:155</a>:14)

    at getChildJsonConfig (<a href="https://github.com/ampproject/amphtml/blob/2012050452002/extensions/amp-animation/0.1/amp-animation.js#L88">extensions/amp-animation/0.1/amp-animation.js:88</a>:23)

    at buildCallback (<a href="https://github.com/ampproject/amphtml/blob/2012050452002/src/custom-element.js#L459">src/custom-element.js:459</a>:39)

    at <a href="https://github.com/ampproject/amphtml/blob/2012050452002/src/custom-element.js#L456">src/custom-element.js:456</a>:38

    at build (<a href="https://github.com/ampproject/amphtml/blob/2012050452002/src/service/resource.js#L343">src/service/resource.js:343</a>:24)

    at build (<a href="https://github.com/ampproject/amphtml/blob/2012050452002/src/service/resources-impl.js#L585">src/service/resources-impl.js:585</a>:29)

    at buildResourceUnsafe_ (<a href="https://github.com/ampproject/amphtml/blob/2012050452002/src/service/resources-impl.js#L520">src/service/resources-impl.js:520</a>:6)

    at buildOrScheduleBuildForResource_ (<a href="https://github.com/ampproject/amphtml/blob/2012050452002/src/service/resources-impl.js#L1205">src/service/resources-impl.js:1205</a>:8)

    at callback (<a href="https://github.com/ampproject/amphtml/blob/2012050452002/src/finite-state-machine.js#L72">src/finite-state-machine.js:72</a>:6)

</code></pre>


Notes

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`@zhouyx` modified `src/json.js:135-158` in #17888 (Sep 5, 2018)

`@alanorozco` modified `extensions/amp-animation/0.1/amp-animation.js:88-88` in #27597 (Apr 16, 2020)

`@rsimha` modified `src/service/resource.js:343-345` in #21212 (May 16, 2019)

`@choumx` modified `src/service/resources-impl.js:1205-1205` in #12311 (Dec 11, 2017)

`@jridgewell` modified `src/finite-state-machine.js:63-78` in #1637 (Mar 18, 2016)

**Seen in:**

- 11-25 Control (2111+2)

- 11-25 Nightly-Control (2111+2)

- 12-05 Beta (0452+2)

- 12-05 Experimental (0452+2)

- 12-11 Nightly (2254)

- +8 more

**Possible assignees:** `@alanorozco`, `@zhouyx`

/cc @ampproject/release-on-duty