Correct, Dale.
Except that a diversion need not be made immediately, you may continue to your latest diversion point in the hope that a further TTF will be released removing the holding requirement.
You must at all times in flight have the fuel on board to proceed to "an" airport for which you have the fuel including reserves and any required holding.
If you have proceeded past your latest diversion point and a subsequent TTF adds a holding requirement for which you do not have fuel, then you have a potential emergency on your hands. You would then need to take safest course of action, which may include landing below minima, landing in a TS, diverting with less than legal reserve, or diverting to a runway normally unsuitable for your aircraft type. None of them are very pretty options, and in the event you survive, would likely result in a safety investigation.
This is why I believe the perceived BOM policy of under-forecasting is bordering on criminal, especially when TS or FG is a possibility.