Trying not to copy errata others have already posted...
Page 44: "Pilot (spacecraft) 3...may perform two Piloting-related" - shouldn't this be "three Piloting-related"?
For Narrative Events where the exact Effect matters, such as when it results in damage that must be rolled, is it Effect 0, Effect 1, or what?
Page 45: cuts off at "allow a pretty accurate reconstruction of who fired from where to be". If that's roughly the end of the intended text, I suggest removing "to be" (and anything that was supposed to come after), replacing with a period.
Page 47: "more dangerous for low END Travellers" is missing the ending period.
Page 48: "(and thus a base initiative) of +1" is missing the ending period.
Page 50: why list END modifier, rather than just saying -3? A disabling wound means END is 0 (and thus END modifier is -3) already (along with DEX and STR) - or do you envision cases where this might not be the case?
Pages 55-56: is the highest gravity category Very High or Extreme? Page 55 lists Extreme but not Very High; Page 56 lists Very High but not Extreme.
Page 86: although it is implied given the other results, results 1-2 and 4-7 on the Starship landing table should say "km".
Page 88: it might be better, on the Strange Animals table, to make the first entry "0-" instead of "0", to clarify that negative results are possible and would not have a worse effect than listed for 0.
Page 90: the Persuade skill implies that a stingstorm is capable of speech. The description does not reinforce this belief. Perhaps a different skill was meant?
Page 99: "1D, 3D" hould be "1D+3D", that being the format (listed on page 87) for Composite.
Pages 132-133: the Port Defence table lists results up to "20 or more", despite being a 2D roll where the maximum DM possible is +6, so the maximum result possible is 18.
Chapter 23 or 25 should probably mention that M-drives drop to 1% efficiency beyond 1,000D from a planet/star/etc., assuming you're keeping that canon from other Traveller editions. This is the big thing limiting approaches to near-c travel: it takes a lot longer once you've accelerated enough that you've moved far enough away from your starting location. (1,000D from Sol - about 1,393,000,000,000 km - is between Jupiter and Uranus. Accelerating over this distance (starting at one end, nearly clipping Sol, and going straight out the far side) at 1-6 G can get you to a few percent of c.
Page 141 says that a crew may have no warning of jump precipitation, but page 143 says that jump precipitation may cause Very Bad Jumps, which are extremely difficult for an entire crew to not notice. Which one is it? (I'd lean toward the former, at least for OTU. The entire Bad Jump system - as listed mechanically - seems to add a lot more danger and misfortune than OTU canon would suggest is typical of jumps. Further, the Jump Variance subchapter suggests it would be routine for highly trained military crews to have a lot less variance than they normally do, and thus conflicts with other canon sources such as Agent of the Imperium, which describes a variance such as listed in Core as routine, expected, and planned for by Imperial naval crews.)
Page 147: "Even with a reactionless drive, a ship will run out of fuel before reaching lightspeed." - Better stated (especially since the sentence before this touched on the topic), "Even with a reactionless drive, it would take infinite time to reach lightspeed."
Page 148: "Unpowered satellites can remain in low Earth orbit for many years providing they are above an altitude of about 150km." For this statement, you want 400 km, not 150. I can claim my own IRL experience/credentials, but Wikipedia's easier to verify:
https://en.wikipedia.org/wiki/Low_Earth_orbit said:
The International Space Station is in a LEO about 330 km (210 mi) to 420 km (260 mi) above Earth's surface, and needs reboosting a few times a year due to orbital decay.
Same page: "1,275,000km, about four times the distance from the surface to the Moon" - 1,275,000/384,400 is about 3.3, which is closer to 3 than 4, so "a bit over three" would be more accurate than "about four".
Page 153: how can a Pilot roll apply to dodge mines if the roller is unaware of the minefield? If you don't know it's there (or at least, where it is), how can you know which way to go? Especially since detection, and acting on that information, is relegated to separate rules.
Page 154: shouldn't the procedures for detecting and getting through a minefield adjust their difficulty based on the density of the minefield? A Minimal field - 8 mines around the entirety of a Terra-sized planet - typically wouldn't present any approaching ship with 1D mines; neither would a minefield of 1,000,000,000 mines (roughly 2 mines per square kilometer a 400 km around Terra).