Thanks a lot @Retired_mod for providing more context for my question. Yes, I've been using CDC in a DLT pipeline and was reading changes to a table from one stage (say, bronze) and applying those to the next stage (say, silver) using APPLY CHANGES INTO. So the target of an APPLY CHANGES INTO operation becomes the source for a change data feed (readChangeFeed) for the next stage. Your post quotes the documentation (which I was also familiar with) in pointing out that "The target of the APPLY CHANGES INTO query cannot be used as a source for a streaming table" so I was using a materialized view to read from that target as recommended.
The error I've been getting since Friday (see my first post, it's a new error, the pipeline was working before) seems to indicate I can't read change data using CDC from a target table of an APPLY CHANGES INTO operation anymore. Am I reading this right?
If so, is an APPLY CHANGES INTO supposed to be the last operation in every pipeline (applied only to my gold tables, essentially)? And if that's the case, what's best practice with propagating changes across stages using DLT?