Stronghold - S9-E14
Revealing mistake: Just after Sam shouts to Mitchell to wait for back up, there is a side shot of a soldier firing a machine gun. There are cases going into the gun without the actual bullet in them, showing they are blanks.
Singularity - S1-E15
Revealing mistake: At the end of the opening credits, they approach a group of three dead bodies to tag them. The second body we see, wearing a light grey shirt, moves its head a little as they are passing the first body. (00:06:00)
Revealing mistake: The shot of Daniel right after Conner says "They only come out at night," you can see the the breath of Daniel. The only time you see that is when It's fairly cool outside. The planet is suppose to be on the warm side. (00:08:30)
Revealing mistake: When Ba'al is making his escape right before the Symbiote gas is released there are two shots of Ba'al clones entering into a room. In both shots one of the Ba'al clones is not Cliff Simon. (00:37:20)
Chosen answer: Report 30185 is a joke report referring to the time when SG-1 go back in time to 1969 in the episode '1969'. The joke is that Colonel O'Neil knocked up a hippie and made sure Mitchel was taken care of throughout his life, like how he got into the 302 program while his buddy, a better pilot, did not.