However, there is also TR_m4_TT_ArmunAdventure_e, but the name of the quest is different, just "Troublesome Orc" without "A". Therefore, it doesn't get hidden from the journal when the quest is finished after inviting him to join the temple.
Ogn in Wetstone Tavern in Gah Sadrith has a Bloodmoon head. Him and his mate Thorhalla (lol) also have the weird purple-ish hair that I think is from Bloodmoon as well, but I'm not certain.
Near Bodrum, in Roth Roryn -14, -18 area, on top of the river near the wooden bridge there is a huge blue arrow visible in-game. It's not visible when you play OpenMW game version, but it's showing up if you play Morrowind on Steam (I've changed versions during the same playthrough).
For some reason TR interior tent doors sometimes do not match the rest of the tent, and the gap to the void of the interior is visible in game. I don't know if it's something prepared for yet not implemented feature, like for example showing some ground from the exterior while being inside of the tent, but I've noticed that several times. Happens in: Velk Camp interior Urvel and Hanneth's Tent Ulyn Menathren's Tent
Selecting the background dialogue topic when speaking with Vycius Pitio spams errors to the warning file and crashes the game. Attempted 3 times and crashed each time. Selected this topic at the end of the IL questline for the questgiver.
During a Thieves Guild quest "Andothren Regained" after killing Vals Varano and using a recall spell to teleport back into the guild hall in Bthangthuv, quest does not progress. Killing all the Camonna Tong attackers does not progress it.
Can be worked around if the quest stage is set to 175 (Bthuangthuv is under attack) prior to teleportation and after Verano's death.
After completing the Cat-Catchers on the Road quest, you are given the Andas Manor slave key to help free the other Andas Manor slaves. Talking to Tejirr, Nirrinirri, or Kenjirha will result in the same response: "You have the key. If you unlock these bracers, %Name can wait for the right moment and escape! Will you help %Name?"
Whilst doing "Jobs at the Docks" I entered Ramaran Manor (while visiting Bodrum for an unrelated quest) and I received the journal entry for being caught trespassing for the later quest, breaking progression and failing the future quest before I could start it.