The Breach - S2-E21
Other mistake: As Archer walks into the sickbay, while the camera pans, you can see a bottle of Crystal Geyser water. I noticed the bottle right away but had to pause it to see the brand. (00:39:00 - 00:40:00)
Other mistake: Two Borg are discovered North of the Arctic Circle. One is covered in ice, the other encased in ice. Carbon dating shows the wreckage to be over 100 years old (to tie it in with Star Trek:First Contact). The Borg are inactive and unable to repair themselves until they are "defrosted". The temperature above the Arctic Circle doesn't usually drop below -100°F. The Borg have been shown to work very well in the vacuum of space which is 3-4K (roughly -454°F). If they can survive that, even being frozen in a solid block of ice would not slow them down. The nanites have to be in their "blood" and operate at the cellular level. That cannot be damaged by re-entry and the crash. [This is one of those entries that keeps being corrected and recorrected - I'll leave it up to people to make up their own minds.]
The Catwalk - S2-E12
Other mistake: The Doctor states that sick bay is the most heavily shielded area of the ship but later in the episode he is trying to move all of his specimens to The Catwalk. If the sick bay is the most heavily shielded area then he would not need to move the specimens.
Other mistake: Just as Malcolm finishes opening the hatch on the alien pod, a graphical mistake appears towards the left side of T'pol's arm. It appears as if a section of the craft had been added with an overlay, which abruptly disappears as the cutting tool stops firing. (00:01:30)
Suggested correction: It doesn't disappear. It just falls into shadow when the cutting beam is turned off.