The issue is exactly as T258833: [wmf.1] MediaSearch page 429 error responses on initial search request but for Other tab. I re-checked the searches for Images/Audio/Video/Categories - the issue is rarely (for complex search queries -three words and more) present there.
Steps to Reproduce:
- On Special:MediaSearch page switch to 'Other' tab and enter simple search query - "kitten", "snow" etc.
- When results appear - scroll down the page - the Console will display many 429 errors.