Movie starts from audio sync time

Hello, good afternoon.

I recently bought the FullUHD of a movie that I liked, I have ripped it to be able to make a lighter version and save it on the hard drive. This movie is a foreign edition (they have only released this edition in 4K) and I have mounted the Spanish audio to the .mkv.

The 4K movie has 40 seconds more opening credits than the 1080p Blu-ray version, with mkvtoolnix I added the Spanish audio and added a 40000ms delay. Once the assembly is finished, I check with the MPC player and it is perfectly synchronized and so far everything is fine, the problem is that I play the movie on the AppleTV and the movie starts from the synchronization and I lose those 40 seconds of credits, even if I manually go back to time 00:00:00 the movie always jumps to time 00:00:40.

Excuse me if I have not explained myself well, I am Spanish and I may have translated it wrong.
Thanks in advance and greetings.

Would you be able to upload a sample video we can review here?