Hi everyone,
sorry for the delay in answering, it's been some crazy months lately.
When we migrated the app to Ionic 3 we had to fix some stuff in Phonegap Build too. In this reo you'll be able to find a configuration that works:https://github.com/moodlehq/moodlemobile-phonegapbuild/tree/v3.5.0
Cheers,
Dani