Service storing Global Varible doesnt work on Device

Hi everyone, I’ve got the following service, which when running on ionic serve, it only calls the rest service once. When running on the device however, it calls this.http.get each time.

Why would it be different in the browser and the device? Anything I can do to fix this?

export class RestApiService {

    wordList: Observable<any>;

    constructor(private http: HttpClient) {

    getDataOnce(): Observable<any> {
        try {
            console.log('getDataOnce() ');
            if (!this.wordList) {
                console.debug('REST API: ' + apiUrl);
                const response1 = this.http.get(apiUrl);
                this.wordList = forkJoin([response1]);
            return this.wordList;
        } catch (e) {


ps I know i don’t need the forjoin.

I am using this service in two modules in my app;


For both of these, I have the following statement in my *.page.ts file

import {RestApiService} from '../rest-api.service';
constructor(public api: RestApiService, ...

And that’s it.