[Q] Android memory issue topic

I have a Galaxy S duos 2 (GT-S7582) and im having what i think is a bug
My phone currently has 1.2gb/2.0gb free internal memory and 2.8gb/64gb sd card but still it refuses to install one specific apk(any other that i try installing works fine)
apk has 4.0mb and i had it installed a while ago so i pretty sure it ins't a memory shortage.

any help appreciated