It was an inadvertent mistake , but it wast like heading or altitude bust in my view...after all we were on our eared flight plan route.
Right... but an airspace bust can be just as bad; just ask someone who's ever "inadvertently" flown into Class B airspace or a TFR without a clearance/prior approval.
14 CFR 91.135 stipulates that in order to operate in Class A airspace, "each pilot must maintain two-way radio communications with ATC." However, even the AIM recognizes that a one-size-fits-all playbook for the abnormal is never going to happen:
It is virtually impossible to provide regulations and procedures applicable to all possible situations associated with two-way radio communications failure. During two-way radio communications failure, when confronted by a situation not covered in the regulation, pilots are expected to exercise good judgment in whatever action they elect to take.
I think... and would hope... that any sane judgment of a situation where no safety threat was imminent and was eventually resolved with no apparent impact to others... would simply get written off. I mean, if you played things strictly by the book with no common sense judgment of its application, apparently you were supposed to plunge through the FLs (and potentially around clouds to remain in VFR conditions) from 410 in order to land as soon as possible.