Now, after we've been through lawsuit filings, discovery, back-and-forth over injunctions and a trial and gotten a verdict... The patent office turns around and says: "On second thought, we shouldn't have issued that patent in the first place.", which itself will be reexamined and appealed and ... adding onto the existing pile of appeals.
I happen to think that the patent office's invalidation is correct, but even if you don't... this is no way to run a railroad. Successful reexaminations should be a rare, exceptional case in a properly functioning patent system. Instead, we have case after case turning on them (Oracle v Google, the Lodys reexamination requests, ...).
Here's a radical idea: Maybe the patent office should work harder to not grant patents it is likely to invalidate later.