Why blame the gear oil for a failure with no proof it had anything to do with said failure? The odds are extrrrreeeemely high that the failure was due to a substandard part from Harley, not a failure of the lubricant. Most of the various lubricants the guys are mentioning are similar to the Redline product btw. And if you're thinking it was because the Redline was too "heavy", that's a misnomer as well. The viscosity is 75w90, just like the stuff Harley sells under the Formula brand name and all those other guys sell as well. In terms of actual viscosity, that 90 weight gear oil is roughly the same as 50 weight motor oil. The motor oil and gear oil scales are not the same. In other words, the same viscosity as that motor oil Harley installs in the CVO transmissions.
Harley has had more than a few failures with the Cruise Drive trans, all linked to the design and the parts. I've never heard of one where it was proved the lubricant failed or caused a failure.
Jerry