Tag is write by some uncertain reason while program no binding and scripting

i have a project which have many memory tag, when my gateway is 7.9 version , it is ok
but after i update to 8.0, these tag will always be write to some data which is out of my control, for the 8M tag, i have make it no binding, but after some while , it will be write to 31
any place can found who trigger this execute? why in 7.9 never have this issue?