Perhaps I'm misreading your tone
You are.
Boney has on many occasions chastised people for 'micro-managing' Mathilde. Pointing out that Mathilde is a highly trained, very experienced and intelligent individual who can be relied upon to be reasonably competent in carrying out the actions we vote for. As such when they asks how she could overcome a simple obstacle, one she overcame just last turn, I assume they are making a joke.
If you think there is an extremely straightforward solution to the mystery that plays to Mathilde's strengths and can be performed with a single AP, then the thing to do is to suggest that action to the thread and try to convince people to vote for it. This constraint on possible solutions that you find 'extremely annoying' is entirely imagined.
Imagined perhaps. But I find it noteworthy that you responded with an aggressive paragraph rather than the usual "try it and find out".
Still if that is your ruling.
Write in action: [] Visit all female-deity worshipping cults in the Old World to see if they worship one of Ranald's Daughters.
[X] Plan Disregard WEBMAT, Acquire AP, Find the Daughters
-[X] One Overwork Action
-[X] COIN: The Father
-[X] WEB-MAT: Hire someone as a full-time Gyrocopter pilot (Adela)
-[X] Lay the foundations: work with the current members of WEB-MAT and the Waystone Project to build a single unified framework for understanding the Waystones.
-[X] Attempt to bring a Major House or Ward into the Waystone Project (Tindomiel)
-[X] Branulhune's ability to disappear and reappear at a thought allows entirely new forms of combat. Continue to work on them.
-[X] Investigate how the Vitae reacts to a power stone.
-[X] EIC: Have the Hochlander set up a shadow headquarters for the EIC in the Sunken Palace.
-[X] KAU: Decide who your library staff will consist of, and go about recruiting them.
-[X] SERENITY: Write a book: Windsoak Mushrooms (1/2)
-[X] Visit all female-deity worshipping cults in the Old World to see if they worship one of Ranald's Daughters.
Modified the leading plan, replaced '[] Attempt to bring a non-Order magical tradition into the Waystone Project (Nordlander Haléthan Hedgewise)'