Two Things Wrong (That I Noticed)
Both having to do with digital editing or at least makeup.
One, Taron Egerton's neck mole should never have been allowed in this movie! What were they thinking? Even if the actor considers it a trademark like Marilyn Monroe's beauty mark, which it is far from being, it has no place in a film about an actual person lacking such a blemish. The zits and five o'clock shadow I can overlook, but this is too much! The first viewing it distracted the hell out of me, and the second also a distraction as I tried looking at anything else.
Two, when Elton and Bernie arrive for the first concert at L. A.'s Troubador, some obvious archival footage appears depicting the area in the 1970s, but not archival enough! A theater marquee advertises "Jimmy Carter Victory Party." Unless there was another Jimmy Carter besides the president, or he did something before being elected to gain attention in L. A., Carter was not elected until November 1976. August 25, 1970 was Elton's first appearance at the Troubador, and they were so careful about other details! When the Troubador's manager waves a newspaper at him on a later appearance, Tora! Tora! Tora! is prominently visible, which did indeed appear in September 1970.