PostgreSQL: Read returning more quickly than write - postgresql

Question

I have two queries written with SequelizeJS
Read:
Object.getObject = async function(){
return await this.findOne();
}
Write:
Object.updateObject = async function(info){
const t = await sequelize.transaction();
const currentObject = await Object.findOne();
const updatedObject = currentObject.updateAttributes(info, t);
t.commit();
return updatedObject;
}
These queries are fired when you go to a URL in an API.
I trigger the write query first, and then in a promise that handles the successful write request, I get the updated object.
API.updateObject().then((res) => {
API.getObject();
})
Despite the GET HTTP request and read query firing after the UPDATE HTTP request returns and is handled as a promise. The read query completes first and returns an object model in a state prior to be being modified by the mentioned write query.
As in, the write query, despite being fired off first and indicating it was complete. Fires off the read query which completes and retrieves an older object modal before the write is complete.
Is there something I don't know with about PostgreSQL and how it handles the sequences of queries when reading and writing to the same object?