Custom variables miss on hangup

I have asterisk 13.10 and freepbx 13.0.192.9, using chan_sip.

Problem:
I have following dialplan:
exten => _8XXXXXXXXXX,1,Noop()
same => n,Dial(Local/${EXTEN}@mroute)

[mroute]
exten => _8XXXXXXXXXX,1,Noop()
same => n,pauseQueueMember(,Local/${AMPUSER}@from-queue/n)
same => n,Dial(Local/${EXTEN}@outrt-3)

and outrt -3 is freepbx generated dialplan.

Problem: I see AMPUSER variable at every step of dialplan execution. But it is lost in H extension.
When I do dumpchan before dial app in macro-dialout-trunk there are folowing variables:

[details=Summary]MACRO_DEPTH
MACRO_PRIORITY
MACRO_CONTEXT
MACRO_EXTEN
ARG1
custom
OUTNUM
TRUNKOUTCID
EMERGENCYCID
USEROUTCID
REALCALLERIDNUM
DIAL_TRUNK_OPTIONS
OUTBOUND_GROUP
DIAL_NUMBER
DIAL_TRUNK
ARG4
ARG3
ARG2
NODEST
MOHCLASS
GOSUB_RETVAL
REC_POLICY_MODE
RECMODE
DB_RESULT
REC_POLICY_MODE_SAVE
AMPUSERCIDNAME
AMPUSER
TOUCH_MONITOR
DIALEDPEERNUMBER
REC_STATUS
RECORD_ID
MIXMON_ID
CALLFILENAME
MON_FMT
FROMEXTEN
TIMESTR
YEAR
MONTH
DAY
OUTpause
TTL
CALLEE_ACCOUNCODE
DIAL_OPTIONS
[/details]

But when I hangup channels I see only this:

[details=Summary]UPQMSTATUS
DIALSTATUS
DIALEDTIME
ANSWEREDTIME
RTPAUDIOQOSRTT
RTPAUDIOQOSLOSS
RTPAUDIOQOSJITTER
RTPAUDIOQOS
DIALEDPEERNUMBER
DIALEDPEERNAME
SIPCALLID
SIPDOMAIN
SIPURI[/details]

When I try to test this dialplan:
exten => 9001,1,Set(testvar=11111)
same => n,Dial(Local/100@from-internal)

I see testvar in dumpchan.

Where could be problem what deletes variables?