Some of this is seen in the latter parts of the Patent Docs post titled Reaction to House Patent Reform Bill-->
In their letter, the groups contend that "[t]he proposed Act has several features that will increase our costs sharply and reduce our access to the patent system, increase the Patent Office's delay and backlog, and decrease our ability to enforce our patents" Among the bill's problematic features is the first-inventor-to-file provision, which the letter argues will lead to a "weakening of the grace period," which in turn "raises risk of loss of patent rights by our members, as it impedes the important process of incubating and vetting inventions."
Of the "weakening of the grace period," the proposed grace period applies only to disclosures. Also, apart from insulating the inventor against the inventor's disclosures, the bill protects against disclosures within a year of another who obtained the subject matter either directly or indirectly from the inventor. If the "another" did not obtain from the inventor (directly or indirectly), too bad for the inventor.
See also the IPBiz post
Demise of the (anti-)Doughnut campaign: a parable of patent reform?
Keywords: S.23, H.R. 1249