Buggy or strange behaviour matching mutable data with `re`

Bug report

Bug description:

import re
data = bytearray(b'1')
match = re.match(b'1', data)
print(match[0])  # b'1'
data[:] = b'2'
print(match[0])  # b'2'

If you match against mutable data (e.g., a bytearray) and change that data after matching, the matched values reported by the match change.

Is this a) a bug or b) strange behavior that should be pointed out in the docs (or c) none of the above)?

CPython versions tested on:

3.13

Operating systems tested on:

Linux

Start by running the provided Python 3.13 reproducer with a mutable bytearray and inspect the resulting match values after mutation. Read the relevant re behavior and existing coverage to determine whether this is an implementation bug or documented behavior. Done means the behavior has a clear resolution, with matching regression coverage or documentation as appropriate.