Et parlant de Twogrey tu l’as fait fuir le pauvre, on a plus de nouvelles de lui xD

Ouais je sais, ça m'arrive souvent.

Sorry for late reply, wanted to finalise everything and then lost track of time.

Made this image to highlight where everything is, it's taken from Edea 1st (may be slightly different values, it's had modifications but the offset structure is the same).
https://imgur.com/a/o8kx2dr

AI offsets are set up as the following:

\\Headers//
At top of enemy file is a bunch of 4-byte offsets. You want the 9th value, which should point to the AI section.

The AI section starts with its own set of sub-headers. The first two values are almost always 03 00 00 00 and 10 00 00 00, followed by two offsets for text strings (even if enemy has no text strings). I've highlighted these in red.

The next set of offsets points at the AI sections: pre-battle, main, general counter, unknown, and death (unknown is used by some enemies but I've not worked with any using this group yet). These are marked as purple.

To find the pre-battle AI group, start from the 14 00 00 00 and count 14h (20) cells. This should bring you to the very start of the pre-battle AI, marked in green. For AI sections, always count from the 14 00 00 00 offset rather than the 03 00 00 00 offset at the start.

Everything in the AI is 4-bytes in length, with the exception of the text string offsets at the very bottom (marked in brown; these are 2-byte offsets that point to the start of text strings, marked in cyan/teal: 03 34 = character name, Rinoa I think).

Because the AI uses 4-byte opcodes, we can check the headers to see if a value is missing. Starting from the 3rd and 4th offsets (for text) and the 5 offsets starting from 14 00 00 00, look for any odd numbers or values which aren't divisible by 4. If there are, then it's likely the editor hasn't parsed some padding properly.

Every AI section seems to end with a 00 00 00 00, and even empty AI sections will have at least a 00 00 00 00 for the offsets to point to. What happens is that this can be mistakenly left as only 00 00 00, causing the AI to run on and cause issues.

Jump to the offset that has an odd/wrong number, and count in 4s to where the next AI section is expected to start (or the text string offsets if the error is in the death AI section). Add an extra 00 if needed.

Now you need to update all the affected offsets. Any offset before this additional 00 is fine, but all AI sections after it will need +1. The text offsets at top will also need +1 because they always point after the AI.

The top of the entire enemy file will also need adjusted; there are 13 of these offsets in total, with AI section being the 9th value, so you have 4 values to adjust (don't go any further than that, the rest of the header is for other stuff).

The 13th value, however, shouldn't be +1 as this should be pointing to the very end of the file and doesn't seem to be getting updated by the editor. Go to the bottom of the enemy file and check the address of the last cell; you want this value +1 for your 13th offset. So if the last cell in the file, for example, is 1B4E7, you're going to set 'E8 B4 01 00' to the 13th offset.