DTMF Meeting - Personal Audioconference

I joined a Zoom meeting using my cell phone and dialing a number from the Global Dial-In Numbers list.
Once inside the meeting, DTMF commands like *6 to open and close the sound and others functions, work normally.
After that, I add a number to my cell phone call (so I pay the call costs). After merging the call, we can normally hear what is said in the meeting. But DTMF commands no longer work, even if I disconnect the other number from this personal conference. The DTMF features only work again if I end the call with the zoom and call the meeting again (Global Dial-In Numbers).
I would like to know how to make the dtmf commands keep working even if I add a person to my personal call.