[nv335]

It may be safe to assume you can't voice-search while the indexer is active.
The question, as you put it, is why the indexer is active again after everything got indexed previously (without the media reinserted).

Here's my theory: the same issue we're observing with "folders disappearing" is actually an error condition with the indexer running out of memory. The error condition likely leaves the collection flagged as non-indexed (partially?) so when the car is restarted at a later time, the indexer attempts to...index again.

Again - only theory, but I may learn more if I manage to get the collection down to a size that avoids the error. I'll see if the problem you're reporting (I'll call it "redundant indexing") also disappears in that case.