Bug/Issue I can't seem to find Secret Note #10. Is this a glitch?

Hi guys,

I have approximately 150 hours played and I unlocked the magnifying glass in Year 2. It is now Year 6 and I have yet to find Secret Note #10.

Notes:
- I play solely on multiplayer.
- My partner and I retrieved the skull key. We entered Skull Cavern and received mail the next day from Mr. Qi. We would get rewarded if we reach Floor 25.
- I reach level 25. My partner gets rewarded for the quest while I don't.
- She is able to find Secret Note #10. According to the Wiki, you must complete the quest mentioned above to get it.

Seeing how I wasn't rewarded for Mr. Qi's Challenge, will I be able to find Secret Note #10 or am I just unlucky?

If worse comes to worse, I am willing to Save Edit my file if it is in fact a bug. If anyone knows how to do this, please help.

Thanks!