[Enkidou]

With the Seattle city edition, now spirits got weaknesses.

What about Street Wyrd spirits?

[Michael Chandra]

Nothing official yet, there's people looking into it.

[MercilessMing]

There hasn't been any errata published for Street Wyrd (or any book other than the CRB as far as I know) so there are no  weaknesses published for Plant, Guardian, Guidance, or Task spirits, and I don't think there have been any comprehensive suggestions made for them yet.  But I believe the intent is that all "basic" spirits - that is, all spirits that players can summon - have a weakness.  So, you should make some up for your home game.

Plant spirits - I think it's obvious - should have a weakness to fire.  And herbicides.

Guardian, Guidance, and Task spirits I think are all based on a bigger Spirits of Man umbrella, so you could have them share the same weakness as the Spirits of Kin, which are also based on Spirits of Man. 
Guardian, Guidance, Task - weakness to iron.

But maybe you can think of something more appropriate for those.

[Finstersang]

Guardian, Guidance, Task - weakness to iron.

But maybe you can think of something more appropriate for those.

A weakness against Iron feels a bit weird for Task spiritis - at least if it´s implemented as an allergy. If it only works as a means to get past ItNM: Sure, why not? But if it prevents a spirit smith from doing smithery, it would be a little counterintuitive. Same is true, too a degree, for Guardian Spirits that are supposed to handle rl weapons.

Whelp. Luckily, I houseruled Hardened Armor, so Spirit Weaknesses are not as important for my tables. The Weaknesses of Elemental Spirits are still welcome, though. Even with houserules, Fire Spirits are pretty brutal  damage dealers