-=[ EDIT ]=-
Ok... So this issue isn't browser specific. It's "logged in" specific! The screenshots of Chromium are from when I was not logged in to the site. As soon as I logged in and rerun the search., I get the same results as when I was running it in Firefox!
-=[ EDIT EDIT ]=-
I found the issue. In my "Buy Parts" settings, I had it set to only show sellers from my country (US). For some reason, I had to disable that and de-select everything except North America. The results still show US sellers, but ... that's just odd. I'll leave this in case anyone else has this same issue.
I am running Firefox v61.0.1 under Ubuntu 16.04 LTS. When I do a parts search for an MOC (this one - https://rebrickable.com/mocs/MOC-10820), first of all I get the "BrickLink API error", but I see that that is due to their server being slow, so I disable the BrickLink search. However, when I run the search, a red box shows up that says:
Total Cost = $0.00 (Includes Delivery Cost = $0.00)
Total Parts = 0 out of 1464
Unique Parts = 0 out of 233
Num Stores = 0
When I scroll down, the table is missing, as are the store names, the piece photos and the stock/price points. I have tried running Firefox in safe mode to disable all addons but nothing helps.
If I run this same search in Chromium (not Chrome... Chromium) v68.0.3440.106 the search runs fine. I am still missing the parts photos, but at least the stock/price points are there.
Anyone else experience this or know what may be causing it?