//receiving struct
struct MyObj{
İnt id;
QTimer *timer = nullptr;
}

//socket tcp 
void readyRead(){
QList<MyObj> objs;

//data parsing here and append list(MyObj)

emit sendObjs(objs);
}


//mainwindow
void receiveObjs(QList<MyObj> objs){
// I control here objs is exist or not 
// I took _objs list in mainwindow and control with new objs list receiving obj id. İf id exist in _objs update pareters, or id do not exist in _objs MyObj append to list

for(MyObj &obj : objs){
İf(do not exist){
//start remove timer 
Obj.timer = new Timer
Obj.timer->serSingleshoot(true);
Connect(obj.timer … {
removeObj(obj.id);
});
Obj.timer->start(15000);

addTable(obj)

_objs.append(obj);
}
else{
// id control in _objs and updare parameters
// timer start again
// addTable again
}
}
//send _obs list to somewhere, it just set to list local as parameters 

}

Void removeObj(id){
//stop timer
//remove from table
//remove from_objs list
}

Void addTable(MyObj obj){
// id check
// if rows has id, update row
// else add new row
}

So, I take data from tcp socket as they are some object and, I send to main for update my list, also I check received objects still exist or not, İf they not remove.

Now. How _objs list address broken?

I have written on mobile device, sorry for bas syntax;

• Uninitialized memory. Debug builds tend to zero-initialize or pad allocations, so reads of uninitialized values accidentally return 0. Release reuses whatever was there.
• Use-after-free. Debug allocators often keep freed memory around a bit longer, so dangling pointer accesses "work". Release reuses memory immediately.
• Race conditions. The slower execution in debug masks timing issues between threads. In release, two threads actually collide.
• Compiler optimizations eliminating reads. If you have a flag or state variable that's written from one thread and read from another without proper synchronization, the optimizer is allowed to cache it in a register and never re-read it from memory.

Regarding WebEngine specifically: it runs Chromium in a separate process, and if your app is doing anything with shared memory, callbacks into QObjects across threads, or raw pointers that get passed around through WebEngine's JS bridge, those are all worth checking.