Getting Access violation executing location 0x0000000000000000 even when accessing from a valid address

I am getting an access violation error. I am attaching pic for more reference. The thing is this doesn’t happen all the time. Its very rare and random. I have no clue why this is happening. Can anyone help me with this? I have given up trying to fix this.

double check you have saved your mesh in a ref variable with TObjectPtr or * , if you used TWeakObjectPtr, garbage collector will delete the object within 1min.