Since we don't know what the rubber bands looked like when they found the bills. is it possible the money simply out lived the bands? could they have failed several years prior to the find, but stayed attached?
You saw the Feynman video. Bands consist of long molecular chains with sulfur bonds. In a relaxed state the molecules want to kink roll back on themselves at an ambient temperature. In a stretched state stress is placed on the atomic bonds bonding the long chain molecules together. Temperature of the bands goes up. As Feynman says these long chained molecules are constantly being attacked by free atoms around them.
In a relaxed state these molecules want to roll up and segment - see relaxed aged band photo.
In a stretched state in a cool environment the molecules will simply lose all elasticity and dry out (possibly crystalise) but the long chain molecules will break into segments, especially at the sulfur bond points, leaving once intact bands as a series of small broken segments of what were once joined molecular groups. The presence of ozone, oxygen, uv light, etc all simply speed this process up.
You can see this 'segmentation' happening in the rubber band at rest photo. This is a chemical breakdown due to the forces Feynman outlined, and the band is not even stretched. If the bands never go above 68*F then they will never enter what is called the 'melt transition phase' which is where bands turn 'gooey' as they degenerate chemically. From all descriptions, the Ingram bands never went through that phase probably because they never were at 68*F or above and those bands simply dried out, went through molecular degeneration and segmented into lots of crumbly particles ... all still in a line with some pieces clinging to the fibers in the paper. That is probably what they mean by "bands were still intact". Any idea that those bands were still viable would require strong proof to believe. And again, only a lab analysis will answer these questions.
I think some of these band fragments still exist if somebody wants to turn them over for analysis.
Conclusion: The news from the bands on the Ingram find is that the money was never at 68*F or above during at least the first several years after Cooper had it. That means it was in a cool to cold environment. This is based on the description of the bands by the Ingrams I have.