When Walt and Junior are first chatting with Hank at his house they leave the front doors wide open. The next shot both doors are closed with no one shutting them or even a sound of the doors shutting.
When Walter is outside Jessie's house trying to call him, the call goes straight to voicemail multiple times. After he breaks in and enters Jessie's bedroom, he tries calling again, with the phone vibrating and receiving a dial tone.
In the intro, Mike uses a lantern in the trailer. He never touches it or turns it off, yet it has disappeared when the trailer doors are opened.
(When the gunmen shoot up the trailer the lantern falls to the floor. It could very well have broken and gone out then.)
When Mike returns the money and Jesse steps over the tied-up person to get it, there is a visible pad on the bottom of Aaron Paul's foot to protect it from getting cut when stepping on any debris on the floor.