Ruby

There is an regex error pattern on ruby 3.2.0. This pattern is success on ruby 3.1.3.
Is this a bug? Or, is ruby 3.2.0 correct?

• ruby 3.2.0

# ruby -v
ruby 3.2.0 (2022-12-25 revision a528908271) [x86_64-linux]
(byebug) MAX_CHAR_LENGTH = 8
8
(byebug) WHITE_SPACE_STR = '[[:space:]]　\uFEFF\u00A0\u200B\u180E'
"[[:space:]]　\\uFEFF\\u00A0\\u200B\\u180E"
(byebug) r = /\A((.{,#{MAX_CHAR_LENGTH}}x)|(.{,#{MAX_CHAR_LENGTH}}a[#{WHITE_SPACE_STR}]+b.{,#{MAX_CHAR_LENGTH}}))[#{WHITE_SPACE_STR}]*\Z/ix
/\A((.{,8}x)|(.{,8}a[[[:space:]]　\uFEFF\u00A0\u200B\u180E]+b.{,8}))[[[:space:]]　\uFEFF\u00A0\u200B\u180E]*\Z/ix
(byebug) r.match('a b')
#<MatchData "a b" 1:"a b" 2:nil 3:"a b">
(byebug) MAX_CHAR_LENGTH = 9
9
(byebug) r = /\A((.{,#{MAX_CHAR_LENGTH}}x)|(.{,#{MAX_CHAR_LENGTH}}a[#{WHITE_SPACE_STR}]+b.{,#{MAX_CHAR_LENGTH}}))[#{WHITE_SPACE_STR}]*\Z/ix
/\A((.{,9}x)|(.{,9}a[[[:space:]]　\uFEFF\u00A0\u200B\u180E]+b.{,9}))[[[:space:]]　\uFEFF\u00A0\u200B\u180E]*\Z/ix
(byebug) r.match('a b')
nil

• ruby 3.1.3

ruby 3.1.3
# ruby -v
ruby 3.1.3p185 (2022-11-24 revision 1a6b16756e) [x86_64-linux]
(byebug) MAX_CHAR_LENGTH = 8
8
(byebug) WHITE_SPACE_STR = '[[:space:]]　\uFEFF\u00A0\u200B\u180E'
"[[:space:]]　\\uFEFF\\u00A0\\u200B\\u180E"
(byebug) r = /\A((.{,#{MAX_CHAR_LENGTH}}x)|(.{,#{MAX_CHAR_LENGTH}}a[#{WHITE_SPACE_STR}]+b.{,#{MAX_CHAR_LENGTH}}))[#{WHITE_SPACE_STR}]*\Z/ix
/\A((.{,8}x)|(.{,8}a[[[:space:]]　\uFEFF\u00A0\u200B\u180E]+b.{,8}))[[[:space:]]　\uFEFF\u00A0\u200B\u180E]*\Z/ix
(byebug) r.match('a b')
#<MatchData "a b" 1:"a b" 2:nil 3:"a b">
(byebug) MAX_CHAR_LENGTH = 9
9
(byebug) r = /\A((.{,#{MAX_CHAR_LENGTH}}x)|(.{,#{MAX_CHAR_LENGTH}}a[#{WHITE_SPACE_STR}]+b.{,#{MAX_CHAR_LENGTH}}))[#{WHITE_SPACE_STR}]*\Z/ix
/\A((.{,9}x)|(.{,9}a[[[:space:]]　\uFEFF\u00A0\u200B\u180E]+b.{,9}))[[[:space:]]　\uFEFF\u00A0\u200B\u180E]*\Z/ix
(byebug) r.match('a b')
#<MatchData "a b" 1:"a b" 2:nil 3:"a b">