Wireless ones better yeah? Like Honeywell hkc , do texe do a wireless smoke?
I mean wireless with built in sounder of course so can act independently , not that it can take the place of a proper fire alarm
Long shot does this have a back tamper switch fitted ,maybe someone modified it or something and it isn't making contact
I don't understand how your exiting engineer mode , so maybe there's an extra switch h somewhere programmed on to a zone or something
Don't worry an expert will turn up soon lol
Don't know dude I am guessing now a little ,
But did you saying pushing button activates on walk test , meaning the lid?
If so can you stretch the spring a little to make sure panel kind is closing it ?
Then I would say check your other detectors
I did one two weeks ago battery change still showed lid tamper , I walked round and found one PIR with a lid loose
If tamper switch is responding then has to be something else
If all options are set to user then you don't need to do an engineer reset