Boolean expression logic law confusion
If you want to obtain a minimal DNF in this way, it is generally a good idea to follow the Quine-McCluskey algorithm (https://en.wikipedia.org/wiki/Quine-McCluskey_algorithm). Otherwise, it is easy to get stuck when you use distributivity to combine each term with just one of several possible partners (if you look at your kmap, this would correspond to arranging the $1$ into pairs in such a way that none of them combine into larger blocks).

One other problem with your computation is that you lost the term $A'BC'D'$ when forming pairs (the reason why you still ended up with five pairs os that $A'BCD$ is covered twice).