Purely speculating here, but sometimes these patches - despite their size - are small adjustments needed to keep the current game online.
For example; there may be some server-side changes being made for NHL 24 and in order to ensure NHL 23 continued to stay online, a patch may have been needed. This patch may have included something as simple as an updated settings file to point NHL 23 to a different or new server.
They may not be able to indicate what exactly was patched without divulging some new information about NHL 24 that isn't necessarily something that the public needs to be aware of.
In any case, it's definitely not something to get worked up about.