At my 300mi first service last weekend, tech was happy to have me sit and watch and prompted me to ask questions. I asked about the cone set/head set issues and he hasn't seen any with the recent years' models. He did just sneak a peek (so he wouldn't have to charge me) and saw plenty of grease/packing - and we discussed what to do if and when I ever felt there might be an issue. After the oil and valve check service - he did an all-over review and was pleased not to find anything of concern. He took it out for a check ride and pronounced it roadworthy. [I bought this Himma from another dealer further away, but took it to this closer dealer for the first service - trailered it up and back]. None of the North Carolina dealers seem to be able to keep Himalayans in stock.
Most every bearing manufacturer has the correct grade of bearing, which is on the bearing as a letter code before or after the number - bearings with just the numbers are unlikely to be the correct grade.
Which includes OEM and most of the proprietary kits like Moose , All balls and Pyramid.
But the suffix is not universal , sometimes X OR J , or both .
Bmw and Guzzi used the same bearings, and Mazda as wheel bearings in the FWD cars , so a search on these might give you a better grade of bearing.
IMHO bearings are best bought over the counter from a bearing specialist who will advise on the correct grade.
He will also stock the correct grease, probably Timken brand but it will be Extreme Pressure, EP for short, and waterproof .
They will last longer if they are preloaded correctly too, the aim is to have around 1 thousand of an inch preload when the bearing is in a unloaded condition, which helps to keep the rollers in the correct alignment.
Not hard to do initially when you are re assembling the forks, but they will bed in and need readjustment after a few hundred KM.
Manual says just remove all play, but you probably want just a little more than that.
It is a bit of a learned skill, the mechanic at my fav dealer/cafe/ servo has that skill and I just give him the $60- and he gets it just the way I like it, first time, every time!
I would guess it's to do with bearing quality, I recently watched itchy boots on u tube & she had two sets of Enfield bearings , both went & then fitted a set she got in Kazakhstan (none Enfield ) & had no trouble after that.
I read somewhere that some who replaced the bearings early found bearings without the /Q ,
/Q bearings and more grease might have been part of the 4 upgrade as they reported little to no grease too and the four bikes have plenty.
Not certain where the problem lies, but FWIW the bearings which were bought and fitted following the procedural I outlined have done 240,000 hard KM on my 240 kg BMW R80 G/S PD, and Mazda front wheel bearings the same size as the Hima bearings can last the lifetime of the car.
NSK HR30205 J , and Guzzi use them at the steering head too.
Checked that Timken link, pretty much confirms my advice to give the pair of bearings 1 thou preload.
FWIW Vincent advised 2 thou on a pair of similar wheel bearings .