With 4.16, the properties of DrawPointAction changed, however the documentation and the Typescript typings do not reflect this change.
In 4.15, one could get the coordinates of the DrawPointAction using the coordinates property.
At 4.16, this property is now called vertices, however neither the documentation nor the Typescript typings reflect this change.
I have not investigated other draw action events so not sure if they are similarly affected or not, but just wanted to give a heads up so the docs and typings can be updated.
Thank you very much for reporting this.
It is a bug in the version 4.16 of the API and will be fixed in the next release. In the meantime you can use the following workaround, instead of evt.coordinates use: