Something is still not sounding right to me. Did they sample multiple bales? If they just grabbed a handful from one, they might not have found the 'hot' bale(s) if nitrate was an issue. And... within a field, there may be 'hot spots' where plants are more stressed and prone to NO3 accumulation, such that some bales may be dangerous and others safe.
Didn't know the state had resumed forage testing; they had stopped doing so. 2018(last year we bought any hay) we borrowed hay probe from the Extension office, sampled our own, and submitted to forage testing labs. I know the vet. diagnostic lab does NO3 testing on forages, but they don't come out and collect samples.
Multiple animals of differing ages dead, and multiple abortions... I'm still thinking nitrates, not mold.
I've seen some pretty moldy stuff fed through the years - and fed some myself, with no issues. Mycotic abortions are uncommon and sporadic... yeah, I know they happen, but in 30+ yrs of diagnostic pathology work - predominantly on food animals - I've only seen ONE case of mycotic abortion in cattle. It's been so uncommon that it would not even be on my radar for this situation unless I was presented with an abortus and placenta that had typical lesions.