Personal example.
In Georgian (a few millions native speakers) we had historically three different independent alphabets: mtavruli, nuskhuri and mkhedruli. All represent same letters, but different ways to write them. Alphabets are represented in Unicode under different code points. Only mkhedruli is used currently (last few centuries) and therefore most fonts have glyphs for mkhedruli only.
Also there is no concept of capitalization in Georgian, there is no "a" and "A", we have only "ა", one does not start a sentence, a word or a personal name with some variant of a letter. Anna is ანნა in Georgian, the first and the last letters are written the same way.
Now, because of some reasons, letters of mtavruli alphabet are registered as uppercase versions of letters of mkhedruli alphabet. Mind blown.
And since well written software uses rules defined by Unicode standard, via ICU library or some platform specific routines, many desktop and mobile applications as well as major web-sites are hard to use. First letters of sentences are capitalized, but since mtavruli glyphs are missing from fonts, they are rendered as ⍰.
So instead of
მაგათი დედაც ვატირე.
we see
⍰აგათი დედაც ვატირე.
and have to guess what was the first letter. But who cares, if it is not used in U.S. right?