Issues with DTMF on E1

Hello, I have 11 Asterisk and Digium E1,
recently I faced with DTMF-signal detection.
I have tried to resolve this by changing relaxdtmf,jitterbuffer,gain but it doesn’t help.
Finally, I realised it cause sometimes singal duplicates (“1” most often), and besides that unwanted signal is very short: 25ms (then normal is about 140 ms):

[2017-05-04 14:40:27] DTMF[5618][C-00006f63] channel.c: DTMF end '1' received on DAHDI/i1/4732330986-364, duration 25 ms.

Can I ignore this short singals somehow?
I found only mindtmfduration, but it seems does another job.