The trick to correcting a problem is to first know what you're trying to "fix".
Sometimes what someone thinks is "the problem" may turn out to be "the symptom" of a different problem.
Trial and error repairs can sometimes evolve into "fix it till it's really broken".
As an armorer, I've often opined to eager, but less experienced, armorers that 95% of "fixing" a gun problem is often correctly figuring out the correct nature of the problem you need to fix.
Once that's done, the remaining 5% can sometimes turn out to be surprisingly simple.
OP, you did the right thing to let Ruger examine the Blackhawk. Not only are they in the best position to identify and address whatever is happening in your Blackhawk, but it's not unknown for repair techs to give a gun the "once over" while they've got it on their bench, looking for anything else that might qualify as a materials or manufacturing problem they may wish to address while they have the opportunity.
FWIW, I've had to return a few older Rugers to the company for repair (70's-90's), including a SBH, Redhawk and a KP90DC. (I was able to identify other Rugers with minor issues and resolve them myself.) They're pretty good about taking care of problems (at least in the manner they believe is appropriate to address them), although many of their fine older firearms are now considered obsolete and are no longer supported by them (including parts), like the Sec/Spd/Serv-Six series and the older metal framed P-Series (like my KP90DC).
Let us know how it turns out. They're good folks.