When Samar is kidnapped the chased van model was different in the beginning of the scene than the one in the final scene.
Lemonade stands are not at all a common occurrence in the UK. Further, lemonade is assumed to be a flavoured carbonated drink, such as 7-UP, Sprite etc.
C-4 is more than powerful enough to penetrate steel backed up with Kevlar. When it's used in an EFP or explosively formed penetrator. Most EFP's are made with plastic explosives (C-4) behind a formed slug of copper, usually concave. That when detonated, liquefies the copper which then forms a high-velocity rod-shaped slug of plasma. That can easily penetrate military grade armor. As a rule of thumb, a Copper EFP can penetrate armor equal to half the diameter of the of the explosive charge. When more exotic metals like tantalum is used the penetration power goes up significantly. So, for almost any given thickness of steel and Kevlar, an EFP could be made.
The photo of the doctor in his office is a portrait (vertical) layout but the camera is held in the reflection as if the photo is in landscape (horizonal) mode.
In addition to the left-hand drive (LHD) ambulance mentioned in a previous goof, every vehicle visible in the UK scene at the start of the episode is left-hand drive, including the two police cars. While left-hand drive vehicles are legal in the UK, any government-owned vehicles would be right-hand drive.
When Keen and Navabi enter the Human Resources department, looking for the suspect, the sign is on the inside of the office door, not the outside.
A US-style "one way" street sign is clearly visible in the chase in Belgrade, Serbia.
The little boy in the opening scene calls his mother "Mommy." English children generally say "Mum" or "Mummy."
In the start scenario, the characters are speaking with American accents. The newspaper later says this is supposed to be Leeds, England - so they should have British accents.
The police cars in 'Leeds' have inaccurately numbered license plates and illegal fonts. The ambulance is a left-hand drive, where it should be right-hand drive. The ambulance also has the medical symbol with snake and sword which is used in the US but never in the UK. The ambulance is also the wrong model for the UK.
When the show transitions to Norfolk, it isn't actually Norfolk, VA as Norfolk is nowhere near mountains or tall trees which can clearly be seen in the background.