My questions are about the game videos below.

https://www.youtube.com/watch?v=KNq35Z8a_QU&amp..............................
At 39:04, Markiplier said "Even though I didn't know that, but it's okay...." Here he used "even though" and "but" in the same sentence. However, English learners were taught to use "even though" OR "but" in our textbook. We can only use one of those two in the same sentence.

https://www.youtube.com/watch?v=f0P6ckIBX6Q&amp..............................
At 7:58, Socksfor1 said "i just saw a body i just saw a body i just saw 'Lit.'" I'm pretty sure he add an "L sound" to the word "it."

https://www.youtube.com/watch?v=Ca8ace1N_4A&amp..............................
At 3:36, Jacksepticeye said "Ironbark Lookout, May twelfthT" I'm also pretty sure he add a "T sound" at the end of the the word, "twelfth."

Why does this happen? Did they make a mistake, or not?

Question

My questions are about the game videos below.

https://www.youtube.com/watch?v=KNq35Z8a_QU&amp..............................
At 39:04, Markiplier said "Even though I didn't know that, but it's okay...." Here he used "even though" and "but" in the same sentence. However, English learners were taught to use "even though" OR "but" in our textbook. We can only use one of those two in the same sentence.

https://www.youtube.com/watch?v=f0P6ckIBX6Q&amp..............................
At 7:58, Socksfor1 said "i just saw a body i just saw a body i just saw 'Lit.'" I'm pretty sure he add an "L sound" to the word "it."

https://www.youtube.com/watch?v=Ca8ace1N_4A&amp..............................
At 3:36, Jacksepticeye said "Ironbark Lookout, May twelfthT" I'm also pretty sure he add a "T sound" at the end of the the word, "twelfth."

Why does this happen? Did they make a mistake, or not?

Answer

greetings

Ill give you an example where you can use ''even though'' ... ''but''
EX -  ''Even though Ive asked you many times to not put milk in my coffee, you continue to do it.  Its like you arent even listening to me.  But, its ok, because you make me laugh.''

Like you stated, it has to be in a different sentence.  my point is there are many scenarios where youd hear an '''even though / but''.  I suppose the person in the video was just talking faster than thinking.

Answer

FIRST VIDEO:  You're right- it's not really correct.  At least at this point in the video he's sort of overdramatizing and is not concerned with correct grammar.

2ND VIDEO: I'm not sure it's an L sound, but he is pronouncing the word strangely.

3rd VIDEO: Yes, he does pronounce it TWELFT. It's incorrect and not a normal thing.

Overall, you might want to find some different youtubers is learning English is your main goal. If you just happen to like these, then you might run into some strange things from time to time.