Bug Report

Ionic version:
[x] 4.x

Current behavior:
Preferred tab as per property selectedTab when opening tabs is not selected

Expected behavior:
Preferred tab as per property selectedTab when opening tabs is selected (as per documentation).

Steps to reproduce:
Take sample code as per https://github.com/ionic-team/ionic-docs/tree/master/src/demos/api/tabs/index.html and put in a separate file with extension html.

Replace code <ion-tab-bar slot="bottom"> with <ion-tab-bar slot="bottom" selectedTab="movies">

Open file in Chrome. Tab movies is not selected.

Related code:
See above

Other information:
Plain javascript file, no framework used. Same issue seems to appear when trying to set selected="true" on ion-tab-button.

Related issue reported https://stackoverflow.com/questions/53860450/ionic-4-preselect-a-tab-in-a-modal. Using selected-tab as property does not work. Using JS is not desired (through controller).

Ionic info:

[WARN] You are not in an Ionic project directory. Project context may be missing.

Ionic:

   Ionic CLI : 5.4.5

Utility:

   cordova-res : not installed
   native-run  : not installed

System:

   NodeJS : v12.13.0
   npm    : 6.12.0
   OS     : Windows 10