Search asset content not working on pdf files

Hi,

I can't seem to be able to search asset content. Perhaps my understanding of the feature is incorrect, so if someone can correct me that would be great too.

Steps to replicate:

1. Become PRO lifetime member
2. Login to your account
3. Upload pdf file to a doc
4. Go to search
5. Switch to search asset file content
6. Search for a distinct word in the pdf file

This results in nothing found.

I can confirm that the pdf file is in the data/asset directory.

I am using web on desktop. I self hosted SiYuan in a docker image on a server with nginx reverse proxy.

Thanks for any help.