No. It reads and records. It never updates, deactivates, cleans or optimises anything – not even when it is sure what the cause is. Isolation testing applies changes only inside an isolated session that requires a signed cookie and an administrator login, and it never writes to the plugin list in the database.
WordPress auto-updates in the middle of Halloween traffic: how to see exactly what changed
Background updates run when nobody is watching, often while campaign traffic is at its peak. Here's how to find out what updated, when it happened and which error lines up with it.