After Effects 2020 not importing the required file I'm trying to import ai file named something 1_03.ai but everytime it shows stubborn behaviour, instead it imports something 1_01.ai I tried something 1_02.ai, but again it imported 1_01.

Then I renamed it to something something else.ai and it imported successfully?



Is it a bug or some feature of Ae aur I shouldn't name them in this way?
This is After Effect's automatic behavior any time it encounters more than one file with sequentially-numbered filenames. It's trying to import them all as entire file sequence. This effectively imports every file, but presents them all as  one single animated footage item, with each file representing one frame.

The solution is that in the "Import File" dialogue box, highlight one or more Illustrator files, and then deselect the checkbox at the bottom named Illustrator/PDF/ESP Sequence.