bug(web): `Error: No matching stub has been registered.`

[sentry]

Not sure what is causing this; 662 errors in last 90 days. The error message could use more context.

Sentry Issue: KEYMANWEB-COM-2C8

Error: No matching stub has been registered.
  at {_ContextManagerBase#2}.prepareKeyboardForActivation (https://s.keyman.com/kmw/engine/18.0.245/src/web/src/engine/main/src/contextManagerBase.ts:315:15)
  at wl.<anonymous> (https://s.keyman.com/kmw/engine/18.0.245/src/web/src/engine/main/src/contextManagerBase.ts:240:37)
  at Generator.next (<anonymous>)
  at None (/kmw/engine/18.0.245/keymanweb.js:1:1396)
  at new Promise (<anonymous>)
...
(15 additional frame(s) were not displayed)