An error occurred while saving the commentMikeM commented
SOLVED . I Just spoke with our dedicated Microsoft contractor whose working on a migration to Teams with us, He confirmed that this is the way it is designed. The main dialpad is only for dialing the initial PSTN number. If you need to then enter a PIN or conference ID or whatever, you need to select the dialpad icon at the top right of the call screen (not the 3 dots as marco stated below). This will bring up a new dialpad where you can input your digits. Very counterintuitive to normal dialing and Microsoft should really rework that or make it a major callout in documentation.