Just spoke to someone at kodak Rochester and found out that the sepia toner was at leats two to three YEARS past expiry date.
I doubt if your issues have anything to do with the "expiration date" of the sepia toner. Like some others said, sepia toner can be kept long, even at working dilution. I have kept both stock and working solutions for very long times.
I've used the Kodak Sepia Toner, but not the second version. What I found interesting was that MGIV, both RC and FB, bleached slowly in the stock solution. Further dilution would probably make it even slower.
I thinks this is the culprit, as this is my experience too. Ilford MGIV (NOT the Warmtone variant), is somehow extremely resistant to bleaching in ferricyanide bleaches as used for two-bath sepia toners.
Of all the papers I have tried (Ilford MGIV RC FB / Ilford MGIV Warmtone RC FB, Agfa MCC, Kentmere Fineprint), Ilford MGIV was by far
the slowest paper to bleach. Even with fresh, manufacturer recommended dilution, it might take 10 minutes for full bleaching. Compare that to maybe just 30 seconds for many of the other papers with fresh bleach
I am still intrigued as to why this is. How can a paper be so resistant compared to others? I have not yet read any good explanation of this. If anyone can shed light on the specific properties of MGIV that cause the resistance, I would be interested to hear...
In addition, the sepia tones of MGIV are very subdued. Even with full bleaching, the brown tones still look quite neutral. For more pronounced sepia tones, and better toning capabilities overall, you should use the Warmtone variant.
Lastly, I think the black specks may simply be residual image silver. Since the process of bleaching takes the image to several stages, it may "appear" that black specks are created, while they are actually small parts of the original unbleached image slightly more resistant to the bleach.