Hangup handler gosub error with asterisk 16.4.0.

Found this on Asterix Users list;
Harley Peters found out that he was receiving errors on any hangup handler subroutines. then he himself found the solution.

exten => 
_1NXXNXXXXXX,n,Set(CHANNEL(hangup_handler_push)=PreventForwardingLoop,s,1)) 
<- shouldn't be there.

Original Message; 

I am receiving the following errors on any hangup handler subroutines.

[2019-05-31 18:22:13.958] VERBOSE[23943][C-00000009] app_stack.c: 
PJSIP/104090401-0000000a Internal Gosub(PreventForwardingLoop,s,1)) start
[2019-05-31 18:22:13.958] NOTICE[23943][C-00000009] pbx.c: No such label 
'1)' in extension 's' in context 'PreventForwardingLoop'
[2019-05-31 18:22:13.958] WARNING[23943][C-00000009] pbx.c: Priority 
'1)' must be a number > 0, or valid label
[2019-05-31 18:22:13.958] ERROR[23943][C-00000009] app_stack.c: Gosub 
address is invalid: 'PreventForwardingLoop,s,1)'

Dialplan:
exten => 
_1NXXNXXXXXX,n,Set(CHANNEL(hangup_handler_push)=PreventForwardingLoop,s,1))


[PreventForwardingLoop]
exten => 
s,1,Set(DELETEKEY=${DB_DELETE(PreventForwardingLoop/${USER}/${CALLERID(num)})})
exten => s,n,Return()

This is one example it fails on all of them.

I have no problems with asterisk-16.2.1 and earlier.
Any idea what the problem is or is this a bug?

Harley Peters