WaitExten problem

In every test, I call an extension from 3000 to 3005, and I then use DTMF to dial 1000. Only extensions 3002 and 3005 work. Other extensions don't recognize the DTMF. I've tried with my phone set to both in-band and RTP signaling.

Dialplan:
[waitexten-test]
exten => 3000,1,Answer()	; Doesn't work
        same => n,WaitExten(10)

exten => 3001,1,Wait(0.01)	; Doesn't work
        same => n,Answer()
        same => n,WaitExten(10)

exten => 3002,1,Wait(0.02)	; Works
        same => n,Answer()
        same => n,WaitExten(10)

exten => 3003,1,Answer(20)	; Doesn't work
        same => n,WaitExten(10)

exten => 3004,1,Answer()	; Doesn't work
        same => n,Wait(0.02)
        same => n,WaitExten(10)

exten => 3005,1,Answer()	; Works
        same => n,Wait(0.03)
        same => n,WaitExten(10)

exten => 1000,1,Answer()
        same => n,Playback(hello-world)
        same => n,Hangup()

What I see during working calls:

DTMF begin '1' received on SIP/redacted-00000006
DTMF begin ignored '1' on SIP/redacted-00000006
DTMF end '1' received on SIP/redacted-00000006, duration 80 ms
DTMF end passthrough '1' on SIP/redacted-00000006
DTMF begin '0' received on SIP/redacted-00000006
DTMF begin ignored '0' on SIP/redacted-00000006
DTMF end '0' received on SIP/redacted-00000006, duration 80 ms
DTMF end passthrough '0' on SIP/redacted-00000006
DTMF begin '0' received on SIP/redacted-00000006
DTMF begin ignored '0' on SIP/redacted-00000006
DTMF end '0' received on SIP/redacted-00000006, duration 60 ms
DTMF end passthrough '0' on SIP/redacted-00000006
DTMF begin '0' received on SIP/redacted-00000006
DTMF begin ignored '0' on SIP/redacted-00000006
DTMF end '0' received on SIP/redacted-00000006, duration 80 ms
DTMF end passthrough '0' on SIP/redacted-00000006

I see nothing related to DTMF during non-working calls.