Any way to fix this? She doesn't stay at the temple and simply returns to jorrvaskr.
She is also my steward, if that has anything to do with it.

A real multitasket. If she's a stewed at one of your HF homes I'd bet it's overriding your Blades summons.

you sent your steward to the blades?

Hearthfire is likely overriding it. My orc married her steward who moved to Hjerim were she had her daughter. Being steward he keeps bouncing between Hjerim and Lakeview