I think last year or so there was an issue where Microsoft Teams broke the phones ability to dial 911 in certain situations. It was something about Teams taking over the dialer or something? I can't recall exactly. Google understandably took a huge amount of flak from users for that and the FCC got involved. It was fixed, but the reputational hit was significant and I'd bet they're a lot more aggressive with any apps that interact with the phone/dialer in general now. Especially ones that aren't being consistently updated.