Twig fence broken despite full claim shield

[Muzk]

Somehow someone magically broke a twig fence off my deed and stole absolutely nothing, like one bone I don't know and left everything else
The entire place is claim shielded

How did they do it?

[reexar77]

Wild animals? boars , bears , anything honestly?

[Granger]

Shield applies to siege operations, breaking stuff by hand isn't in that category...

[qoonpooka]

Somehow someone magically broke a twig fence off my deed and stole absolutely nothing, like one bone I don't know and left everything else
The entire place is claim shielded

How did they do it?

granger answered the most of your question, but for completeness' sake: They have trespassing and Vandalism (and theft if they took something) and used the 'destroy' action. You should build a pali ASAP. This attacker likely concluded, if you're still living under a stick fence, that your stuff wasn't worth stealing... the next may be less forgiving...

[Sevenless]

Generally, people won't raid twig newbie places because the potential for nidbane attacks from an established village isn't worth the stuff a noob would have.

But that doesn't stop people from being dicks, it just discourages them from it.