I’ll take a stab at it because it seems no one else has yet.
Pandas were supposed to be “super linear” switches, and they were produced by a dude/company named Invyr (u/zisb on reddit; hence Invyr Pandas). As far as I can tell, they’re made in the same factory that produces BSUN switches, and seem to be most similar to some offshoot of outemu switches (say this because pandas fit in outemu hotswap sockets, which cherry mx/gateron/kailh do not).
As a group buy they weren’t super popular, although about 10,000 of them definitely sold according to GH MOQ (hence, rarity). Now keep in mind they were billed as linear switches, and as linears they weren’t extremely successful. Pretty scratchy, and nothing to write home about although idk what was available in the community at the time as I just got into this scene a few months ago.
However, I think it was the peeps at top clack that first had the idea to put the stem of a Halo switch (which comes with its own fair share of drama) into the Panda housing, and the holy panda was born. Moulds were apparently destroyed because the switch was never really supposed to get a R2, and Chinese manufacturing isn’t big on keeping useless things just lying around. It wasn’t until the Holy Panda hype train left the station that it was discovered that the molds had been destroyed, and although Pete at 1Up has been collaborating with Invyr to try to get r2 to market, their efforts have been unsuccessful.
Hope this helps; I bought mine when the market was a little bit less scarce, and highly recommend you at least try them out. Or don’t, because you’ll then have to drop $300+ to build a keyboard of them.
Also, having perused the reddit post, the guy seems to be full of snake oil. If dedicated dudes like the OG creator and Pete can’t get them made/remade, then it seems pretty suspicious that old molds were found, out of the blue, more than a year later. Someone’s being fed some poop, whether the IC OP or the community at large.