Steps to reproduce

vim -u vimrc min.rb
nvim --clean min.rb

vimrc

se nocp
syntax on
filetype plugin indent on

min.rb

{a: 0}

Moving the cursor to the } position does not highlight {.

If you comment out the following line in line 471 of ruby.vim, the problem will no longer occur.

$VIMRUNTIME/syntax/ruby.vim

syn match rubySymbol "[[:space:],{(]\%(\h\|[^\x00-\x7F]\)\%(\w\|[^\x00-\x7F]\)*[!?]\=:[[:space:],;]\@="hs=s+1,he=e-1

Environment

NVIM v0.8.0-dev-845-gf38c05bec
VIM - Vi IMproved 9.0 (2022 Jun 28, compiled Aug 9 2022 21:41:53)