hip and valley rafter prop brace or load bearing?

[Randall Clark]

With a hip roof, sometimes the vertical 2 x 4 braces under the hip/valley rafters are flimsy and other times appear substantial (several 2 x 4's nailed together and resting on a 2 x plate). Any ideas on how to tell if these are/should be providing support vs. a temporary brace used when constructing the roof framing? 2 x 4 in photo has been pushed off to the side by stored items and is not attached to the floor any longer.

[BridgeMan]

Most of them (all of them?) I've encountered over the years were temporary braces installed by framers as they were working the roof. Not required once all roof framing is in place, unless extremely long valley spans (with inadequate section modulus of member) may have required it.