Is there any additional information that I can provide?
Syntax error is still getting thrown. Here is the info from context [ext-local] for extensions 1000 and 1001.
exten => 1000,1,Set(__RINGTIMER=${IF($[${DB(AMPUSER/1000/ringtimer)} > 0]?${DB(AMPUSER/1000/ringtimer)}:${RINGTIMER_DEFAULT})})
exten => 1000,n,Macro(exten-vm,1000,1000,0,0,0)
exten => 1000,n(dest),Set(__PICKUPMARK=)
exten => 1000,n,Macro(vm,1000,${DIALSTATUS},${IVR_RETVM})
exten => 1000,n,Goto(vmret,1)
exten => 1000,n,Goto(from-internal,1000,1)
exten => ${VM_PREFIX}1000,1,Macro(vm,1000,DIRECTDIAL,${IVR_RETVM})
exten => ${VM_PREFIX}1000,n,Goto(vmret,1)
exten => vmb1000,1,Macro(vm,1000,BUSY,${IVR_RETVM})
exten => vmb1000,n,Goto(vmret,1)
exten => vmu1000,1,Macro(vm,1000,NOANSWER,${IVR_RETVM})
exten => vmu1000,n,Goto(vmret,1)
exten => vms1000,1,Macro(vm,1000,NOMESSAGE,${IVR_RETVM})
exten => vms1000,n,Goto(vmret,1)
exten => 1001,1,Set(__RINGTIMER=${IF($[${DB(AMPUSER/1001/ringtimer)} > 0]?${DB(AMPUSER/1001/ringtimer)}:${RINGTIMER_DEFAULT})})
exten => 1001,n,Macro(exten-vm,1001,1001,0,0,0)
exten => 1001,n(dest),Set(__PICKUPMARK=)
exten => 1001,n,Macro(vm,1001,${DIALSTATUS},${IVR_RETVM})
exten => 1001,n,Goto(vmret,1)
exten => 1001,n,Goto(from-internal,1001,1)
exten => ${VM_PREFIX}1001,1,Macro(vm,1001,DIRECTDIAL,${IVR_RETVM})
exten => ${VM_PREFIX}1001,n,Goto(vmret,1)
First thing, your call trace showed you push 3, but there’s no option 3 in the ivr-4 context you showed above. Perhaps if you put a valid call trace and a copy of your extensions_additional.conf on pastebin someone might have some thoughts.
However, FreePBX should be re-creating the files on every reload, so if there was an error we’d all be seeing the same error. This leads me to believe there are other underlying issues. Are permissions good on /etc/asterisk/extensions_additional.conf? Maybe try re-installing the IVR and framework modules? Have you deleted and re-created the IVR?
The only time I’ve ever had “ast_expr2.fl: ast_yyerror(): syntax error” was when I moved config files from one PBX to another, on different Asterisk versions. A reload fixed everything up. Would be nice if Asterisk gave a line number on the error!