why do subs change when a game starts?

[Reece p FC]

getting really sick of going to make a sub to find my 1st sub has been replaced by my 1st reserve, why the hell does this **** happen? and is there something we can do? i cant see what as you never know when it will happen, but it's far too often

[milpol]

I had the same problem before a week on the asso games. Its been reported . Thanks for sharing it .