Okta angular can't compile with "ng build --prod"

We are using Angular 8 with the latest okta-angular package. Using “ng serve” works, but when compiling with “ng build --prod”, the build fails with the following error:

ERROR in Can’t resolve all parameters for OktaAuthGuard in //node_modules/@okta/okta-angular/okta-angular.d.ts: ([object Object], ?, [object Object]).
Can’t resolve all parameters for OktaAuthStateService in //node_modules/@okta/okta-angular/okta-angular.d.ts: (?).
Can’t resolve all parameters for OktaCallbackComponent in //node_modules/@okta/okta-angular/okta-angular.d.ts: ([object Object], ?, [object Object]).
Can’t resolve all parameters for LoginPage in //src/app/pages/login/login.page.ts: ([object Object], [object Object], [object Object], [object Object], [object Object], [object Object], [object Object], [object Object], [object Object], [object Object], ?).

Please advise

I’d recommend you enter an issue in this project’s GitHub repo. The README says it should be compatible with Angular 7+.