When I need to call in I tend to do it later in the evening when I would guess call load is lower, so it seems plausible I've spoken with the same agent twice... but it's only happened once that I am certain of, because the agent has a particularly distinctive voice and said up front "this is ___ in ___" identifying which call center they're in. (To be clear, this was across two unrelated calls, not a HUCA)