@csymonsWhen you purchased the US roaming add-on that included Talk, maybe you missed the big disclaimer below:
Important: Important: As of February 22nd, 2022, United States (U.S.) carriers have started turning down certain 3G/HSPA networks. As a result, customers using U.S. roaming add-ons will be impacted by differences in coverage or service quality (including 9-1-1 calls) when roaming in the U.S. Customers may also experience changes to services such as welcome messages, voicemail notifications, usage notifications for voice, notifications when trying to make an international call, interactive voice responses (IVR), as well as the ability to set up voicemail while in the U.S. This shutdown will not impact your service in Canada.
Now because of this, now only data and texting features should be expected to work reliably while in the US, while Talk is a big maybe. The "maybe" because even though both of Public Mobile's roaming partners AT&T & T-Mobile have shut down their 3G networks, T-Mobile still has a small/sparse 2G network footprint remaining in some areas, and if your phone is roaming on T-Mobile (not AT&T) you may be able to complete some calls, but the quality/reliability will be unpredictable, as you have noticed.
Public Mobile does not support Voice-over-LTE, and in Canada falls back to a 3G network for talk. Since there is no 3G network anymore in the US, the phone will then fall back "even further" to that T-mobile 2G network, or fail completely if on AT&T. This may eventually improve if Public Mobile ever adopts the VoLTE feature in the future, but there is no known date to expect this at this time, and things generally change pretty slowly.
As such, your best options for reliable voice calling while in the USA is to use a local SIM from a USA carrier directly or one of the many reseller/MVNO brands (ie Lyca Mobile) or use a calling app like TextNow that gives you a Canadian phone number to make and receive calls over your mobile data or any Wi-Fi connection.
