Continuity mistake: When we first see Mason he puts his hat on the table by his phone. His hat then disappears from the table only to be replaced by Mason when Gibbs walks in. (00:06:20)
Continuity mistake: When the grandfather is talking to Bibbs and gets the phone call his hands/arms are off the table. As the shot changes to a longer one, his arms are now on the table. (00:08:09)
Continuity mistake: When speaking to Conrad about taking the internship at NCIS, the clock behind Conrad changes drastically. (00:04:25)
Continuity mistake: The way Abby holds out the bells for the intern to wear changes depending on the shot. In one shot she has the string over all 4 fingers and in another only over 1. (00:09:20)
Continuity mistake: The writing on the board changes style at the very start. Note the 1st A in Satan. (00:00:15)
Chosen answer: It is never stated, however she must have been there several years if she is on presidential detail.