Entities that use large amounts of power (like beacons and laser turrets) aren't fed as much electricity as they apparently need when adjacent to a Roboport which supplies power; I'm assuming it is powering them from its internal accumulator, thus the limited throughput?

Mmmh, actually all power related feats are done with the use of a dummy power pole entity which is exactly like a regular power pole, except for the fact that it's invisible, frozen (so that the player can't interact with it) and is placed over each roboport.

So, as far as I can tell, the roboport power field should behave as any other power field in the game... this is odd indeed.

Im firing up the game right now and doing some tests, let's see what's happening

Thanks for your submission

EDIT: Ok i've been doing some tests and i seem unable to replicate this issue. Can you check that this isn't happening due to a power shortage, most likely caused by roboports charging their internal batteries? If you connect a lot of them at once (especially if upgraded) it's pretty easy to overwhelm your power plants, which in turn may be erroneously seen as a lack of throughput. This is the only reason that I can think of, since there's no actual "throughput" here.

Anyway, can you give more specific details on how to reproduce this bug?