Browser: Chrome, Firefox, and Safari
Background: The Icelandic alphabet contains a couple letters not present in most other Latin-script alphabets. In particular, the letter Þ/þ (thorn) isn’t used in any other modern alphabet afaik.
A while ago, after setting my common name location preference to Iceland to test out the Icelandic common names I’d added to some birds, I noticed that the second letter in each name was automatically capitalized in common names starting with Þ in certain parts of the website. Here are screenshots of a few examples (from a taxon page, the search bar in the header, and Explore/Observations Search, respectively):
You can replicate this issue by setting your common name location to Iceland, then searching for any of the following species with Icelandic common names starting with Þ: Phalaropus fulicarius, Glareola pratincola, Thalasseus sandvicensis, Xema sabini, Lanius collurio, Sylvia communis, Turdus atrogularis, Anthus pratensis, or Carduelis carduelis.
This issue seems to occur in parts of the website with more recently-updated formatting, including in Explore/Observations Search, Identify, on taxon pages, and on individual observations, in each of the three browsers I checked. One place it doesn’t occur is the old observation list linked to on a person’s profile (i.e., /observations/[username], not /observations?user_id=[username]):
It also doesn’t occur on the iOS app:
(A couple other letters in Icelandic that are only found in a few other languages are eth (Ð/ð) and Æ/æ, but the former isn’t found at the beginning of any words in Icelandic and the latter doesn’t seem to cause autocapitalization issues as far as I can tell.)