I am running beta 13 for Windows, but the issue (described below) seems to relate to the expertise that people on these forum possess, so I'm posting it here too, in case somebody here can help (and doesn't read the Windows beta testing forum). So, apologies for being a bit off topic.
I have reported (on the Windows beta forums) several problems with current spelling (using UK English dictionary, but I think some are common to other dictionaries). Many seem to arise from certain characters (e.g. numerals) being treated as alphabetic characters and so any series of characters that includes them gets a squiggly red underline to show that it's a mistake. Examples include ratios and times (e.g. 3:1 or 12:35pm).
I've had no response from the devs, who are presumably very busy with more urgent matters, so I have done a bit of digging.
Scrivener 3.0 uses a public domain spelling checker called Hunspell, whose dictionaries have two parts: a *.dic file (word list) and and affix file (*.aff) that includes various rules, such as the character encoding needed for the language. I can see from the various bits of online documentation that an affix file can contain an "exclude" command. See: http://manpages.ubuntu.com/manpages/xenial/man5/hunspell.5.html
The limited documentation I've found suggests that this command ought to allow you to specify that certain characters can be excluded:
Sets characters to ignore dictionary words, affixes and input words. Useful for
optional characters, as Arabic (harakat) or Hebrew (niqqud) diacritical marks (see
tests/ignore.* test dictionary in Hunspell distribution).
However, I have not been able to find the "ignore.* test" file that is mentions, nor any explanation or examples of how to use this command.
Is there anyone on these forums who knows more about his and could help?