I'm new and this is my very first campaign. My character is a PF1e cleric following Ptah. I chose the Travel domain and Ash subdomain during character creation. Ptah is associated with the Artifice, Earth, Fire, Knowledge, and Travel domains. We just leveled up to 3, and are picking our second feats.
I read several cleric guides and they all highly suggested taking the War Blessing feat. Some of them even suggested that the feat isn't limited to just my own deity's domains, but to any domain, which seemed like a stretch to me. However, none of them said that the feat would be limited to only the the two domains a cleric choose at creation.
War Blessing
Your fervent call to your deity imbues you with a temporary blessing.
Prerequisite(s): Mystery or domain class feature.
Benefit: Choose two warpriest blessings when you take this feat. Each of these blessings must be tied to a domain granted by your deity or to one of the two domains that represent your spiritual inclination and abilities. Twice per day, you can call upon the minor blessing from one or the other of your chosen blessings. This ability otherwise acts like the warpriest blessings class feature. Your effective warpriest level is the highest level that you have in the class that has the mystery or domain class feature.
However, my GM temporarily ruled that, even though I met the prerequisite (have the domain class feature), I could only use it to take the warpriest Travel blessing, which is essentially just a copy of the cleric Travel domain power, so redundant. And even though the feat says to take two blessings, he says I can't because Ash is asubdomain and not an actual domain, so I can't even take the Fire blessing.
This interpretation seems extremely restrictive, to the point that this feat is completely useless to the whole cleric class. Why would I take this feat just to get two blessings I already already possess as domain powers? I believe that the feat means I can take two domain powers from any domain associated with my deity, not just my single domain. He said if I can find a ruling or SRD entry that supports that specifically, he'll allow it.
Edit to add: He allowed it! Thanks everyone!