Yeah, I just had a >1000 hand iPoker speed session and didn't have hud on most of the time... This has happened to me before, but usually the HUD works ok with 4 speed tables and certainly once I restart the poker client and PT4. I had the HUD at first when I started the session but then at some point the HUD disappeared AND ALSO the hand import stopped.
But fortunately I had the logging on, so I'll just zip my logs from today and create a support ticket and attach the PT4 + HUD logs there, hopefully that might help solve the issue.
Note that once I had played a few hands and the HUD didn't appear, I closed down the iPoker client, stopped hand import (actually PT4 jammed totally when I pressed the stop getting hands, it didn't copy the hands to the processed folder as it usually does, just didn't do anything...) and closed PT4. Note that at this point (after I had exited PT4) the PokerTracker4HUD-process was STILL running in the task manager, maybe it was also jammed somehow? I just killed it, restarted PT4, pressed the get hands while playing and then started the iPoker client and opened up a few speed tables and sure enough it was importing hands (and it imported immediately the ~20 or so hands that were played after the hand import stopped initially before shutting down PT4 etc) but no HUD.