The English credits of 36 Crazy Fists show these credits.

producer: Chiang Kit = Jintana Ferreira / Cheung Git (3)
planning: Chang Chuan
ass. prod. manager: Teng Lun
music: Wu Ta Chiang
???? production: Teng Wei
Sets: Yang Shih Jen
Made up: Chang Liang Yu
Costume: Ma An
Still photos: Chou Pao Che
?????????(camera?): Chen Ching Chu = Chan Ching Kui
cameraman: Pan Te Yeh
Lightning: Chen Lun
Screenplay: Szu Tu An = Sze To On
Continuty: Kuan Yao Yung
Ass. director: ?eng Yun Chung = Pang Wan Chung???
Kung Fu instructor: Jackie Chan.
director: Chen Chin Hua = Chan Chi Hwa

actors:
Hsiung Kuang = Tony Leung Siu Hung
Liu Chia Yung = Lau Kar Yung
Jen Shin Kuan = Yen Shi Kwan
Ku Feng
Mi Hsueh = Michelle Mai Suet ?
Chin Pei = Paul Chun Pui
Feng Ko An = Fung Hak On
Shan Kuai = San Kuai
Chen Liu = Chan Lau (3)
Chiang Cheng
Li Wen Tai = Li Man Tai
Pe Sha Li = Pa Sha Lik
Ma Han Yuan = Ma Hon Yuen
Hsieh Ti

Why fake? Here's a gallery of the "behind the scenes" footage from The 36 Crazy Fists, and Jackie is in it .

I will study them tomorrow.

From Tony Leung Siu Hung interview:

HKCinemagic : In 36 Crazy Fists, you were directed for the action by Jackie Chan. How was your collaboration?

Tony Leung Siu Hung : We know each other since we are little boys. But we have different styles of action choreography. I got some difficulties working with him because of this difference.

(...)

It's changed.
The HKFA credits Jackie for MAD too.

(Still the credit on the edition I have looks a bit strange. All the credits are like in the lower part of the attached image, only Jackie's credit is different.)

Image attachée

I have the same version too. Probably it was changed after JC success, to promote the film. They spotted Jackie Chan in the cover of the dvd and on the beginning of the film too.

You are probably right.

Yep, that's exactly what happened.