i18next: Regression in 2.3.5 -> 2.4 update

Since updating from v2.3.5 to v2.4.0 (v2.4.1 changed nothing so the bug is in 2.4), I have the following issue:

If I try to access a key using t("a::b.c") (a is the namespace, b is the key and c is the subkey), I get the b.c string. Previously, it correctly returned the value of c in the a.json (namespace) file:

{
  "b": {
    "c": "My translated value"
  }
}

This happens in the front-end. I can post my configuration if you need further information to help pinpoint the issue. Thanks!