I've just purchased a new mic adapter for osmo pocket, not the original one. It works fine.  I don't have original mic adapter so I can't compare, but it sound greater than internal mic.
https://www.amazon.com/gp/product/B082B4SK8Q/ref=ppx_yo_dt_b_asin_title_o02_s02?ie=UTF8&psc=1

You can verify if it's working or not, simply by scratching your external mic really slowly and carefully with your nail then see the level changing.

Yes, I did scratching the mic and hear noise. Also, mic level is changing. Anyway, I'm happy with the purchase, but I don't know how long it will last.

Hello there AndyUS19. Thank you for reaching out and for sharing these information about the mic adapter you have purchased for your DJI Osmo Pocket. It is great to know that the said adapter works and just a friendly reminder that there is a possibility that these 3rd party accessories ( mic adapters ) will be able work on the said camera but however, since it's not optimized and tested by DJI we cannot guaranteed the stability of the said 3rd party accessory if it will work all the time with no issues. Thank you and please stay safe always.