i think itt explain as to why go around mode engages!
BUT IF YOU think!
if you have a engine fire
AND FMGC DETECTS it
"One engine master switch off, or
N2 below idle, or
One thrust lever angle is below 5° with the other above 22°, or
The FADEC shows an engine fault."
IT wouldnt have levelved off to accelarate in the first place,(maybe becos yo have mentioned that your engines were still producing power)
chances are fmgc thought you are on both engines
in my opinion
in a case like that ! if your engine out accelaration alt is higher than accelaration alt . you should select speed! if not at accelaration alt push v/s 0, to clean up!
and performance criteria for flex ! assumes that you will clear all obstacles on flx temp on an assumes engine failure after v1!
unless theres something unusual which would effect your climb
( structural damage, higher temp.... )
you will not require TOGA
since your fmgc thought you are still on both engines
it shifted from TAKEOFF to CLIMB phase!
that could be the reason why you got GO AROUND TRK on application of TOGA!
GO AROUND MODE ENGAGEMENT
The flaps lever is at least in position 1, and
The aircraft is in flight, or
The aircraft has been on ground for less than 30 seconds (AP disengages and can be re-engaged five seconds after lift-off).
The FMA displays "SRS" and "GA TRK" in green.
IN all Phases only time you will have flaps lever 1 is APPCH PHS/Takeoff phs, the little time spent accelarating after takeoff phase to flaps 0(climb phase)
so GO around can engage provided it meets other requirements