isCustomElement in Jest

I have Jest configured containing transform options:

module.exports = {
  // ...
  "transform": {
      ".*\\.(vue)$": "vue-jest",
      "^.+\\.js$": "babel-jest"
  },
  // ...

I need to use isCustomElement which is now required at compilation time, so I’ve added options based on the proposed solution in Vue3 docs with Jest transform options:

module.exports = {
  // ...
  "transform": {
      ".*\\.(vue)$":  ["vue-jest", {
        compilerOptions: {
          isCustomElement: tag => tag === 'my-custom-component'
        }
      }],
      "^.+\\.js$": "babel-jest"
  },
  // ...

However it’s still throwing a Vue warn when running tests:
[Vue warn]: Failed to resolve component: my-custom-component.

(I’ve managed to make everything work correctly in a normal vue-cli environment according to this comment.)

Any ideas how to make isCustomElement work with Jest?