A content publish broke our prod build, was it because we did not pin the slot version?

Someone on the content side published a schema change to a slot and our Next app immediately started getting content that did not match our types. Here is what I checked so far:

• the deploy that broke was not ours, no code changed
• the timing lines up exactly with the publish
• we fetch the slot without a version in the ID

My theory is that the missing version is the whole problem. Can someone confirm the safe practice before this bites us again