Intune iOS User-Based App Targeting

The filter only applies to the assignment where you attached it; it is not a global filter for the app. Your Required assignment is limited to corporate-owned devices, but Available for All Users is a separate, unfiltered assignment. Personal enrolled devices therefore still receive the Available intent.

Apply the same corporate-owned Include filter to the Available assignment, or replace All Users with a narrower user group and filter that assignment too. Microsoft recommends avoiding overlapping assignments with different intents because Intune resolves them per user and device, which can make results confusing.

Available should only expose the app in Company Portal, not silently install it. If it actually auto-installs on a personal device, use Troubleshooting + support for that user/device, inspect Managed Apps and the resolved intent, and look for another Required assignment, device-group assignment, or older VPP assignment. Then sync the device after correcting assignments.