older (V4) ASPIRE with PRI.
ext has call fwd off prem .
Call comes in, then transfers out. On the transfer, the number called is heard as DTMF to the calling party.
14-01-10 is disabled.
Any other spots?

I wonder if the off premise forwarding is set up correctly. That has to be set at the phone - but it sounds like it's set more of a fixed call forward with an off-premise destination?

seems to occur either via set by phone or via 24-06.