Automatic DTMF press happening in Asterisk

I’m using Asterisk 13.16.0 with DAHDI. I’m facing some auto DTMF pressing issue. How could I fix the auto DTMF issue? What does mean the below DTMF messages? Below DTMF are not user inputted, these are automatically generating. I want to prevent it.

[Jul 25 08:49:44] DTMF[49528][C-0000a90d] channel.c: DTMF begin '1' received on DAHDI/68-1
[Jul 25 08:49:44] DTMF[49528][C-0000a90d] channel.c: DTMF begin ignored '1' on DAHDI/68-1
[Jul 25 08:49:44] DTMF[49528][C-0000a90d] channel.c: DTMF end '1' received on DAHDI/68-1, duration 89 ms
[Jul 25 08:49:44] DTMF[49528][C-0000a90d] channel.c: DTMF end passthrough '1' on DAHDI/68-1

Stay completely silent. This is probably talk-off, where speech mimics the DTMF tones. It is a natural consequence of using in-band signalling.