Throughout the series, the burn on Elizabeth's right forearm appears and disappears.
This show, like many from Hollywood that show a lot of gun use, routinely plays a sound effect of a gun being cocked whenever a gun is seen on screen. Often the gun shown either has no external hammer and cannot make the sound played or it has already been fired, negating the ability to cock it.
Montenegro, as a former part of Yugoslavia, and a present day republic, has not had any associations with "royalty" since 1918 with the fall of the Habsburg Empire. There would not be any "Princess Sophia", let alone one politically acknowledged or receiving any extra attention or protection from the FBI.
During various operations in Europe, cars are seen with the blue "EU" stripe along the left edge of license places even in countries that are not EU Member States.
After Karakurt (No. 55) (2015), it makes no sense for the Cabal to spin any elaborate assassination plots for any targets whose DNA they can obtain because they now have the proven capability to target anybody with a highly specific genetically manipulated virus that will spread from person to person but kill only the intended target, or at most them and some close relatives with the same genetic markers. All they would need to do is make the virus, infect somebody in the target's vicinity and wait for the target to get infected.