Some minor text issues in Buried Secrets:
Mission 2: The Warrior boss, Treasure Seeker Jones, says "Striga is a goldmine if you just dig a little underneath the surface." Gold mine is two words.
Mission 4: Straxt's post-acceptance text reads "The banished pantheon can't possibly know what they have stumbled upon." Banished Pantheon is a proper noun, and should be capitalized. There is a similar issue in the arc's Souvenir.
And the below "issues" are not strictly wrong, just things that stood out to me reading all of the text. They're wrong in my opinion, but opinions differ.
Mission 1 & 2: Both of the collection clues ("Ore Samples" and "Crystal Fragments") are written completely in past tense in an odd way. Item-based clues are usually written in the present tense, as if you still have the item in question, rather than being written from the perspective of having already given the item away.
Mission 2: The "Crystal Fragments" clue makes mention of multiple crates, when you the player only collect one glowie.
From the Souvenir: "but why did they need research on volcanic activity, ore samples and comparisons to distant soils in Italy, inert dark crystals and weapon prototypes to employ them?" I believe there should be a comma after "inert dark crystals" (the "Oxford Comma", which is the default in American English).
Also from the Souvenir: "The oberst claimed that it was all very much outdated but still too dangerous to end up in the wrong hands, but surely there must be more to it. A mystery for another day, and another paycheck." "surely there must be more to it" feels like it ought to end in a question mark, given the next sentence.