[Username1]

Well here is my thinking...
The horiz driver transistor, 67v 2.x, and 2.x tells me that it looks to be within reason given something is wrong elsewhere in the immediate area.

The large signal on the base of the HOT leads me to think possibly open 1.5 ohm resistor in the secondary of the coupling transformer... You should check that.

Then there is that diode in the collector of the HOT. That diode is to arrest, or stop a sharp negative pulse coming from the HVT when the transistor turns off. If this diode was not turning on fast enough would there be a sharp negative pulse there, and would it be traveling back to the coupling transformer???? It could also be allowing the HVT to be producing those jail bars.... Its all reason, What's going on, and testing. There are some clues around that area, so its just trying to see what part could reasonably be bad, still let most of it work properly, but still be causing some minor problems.... That doide, If you have a new one, might be smart to put it in since it will be spec. when you do....

And on that picture tube discharge, on all tube sets there is more likely a long term charge held, but on a trippler set there are little bleeder resistors, and leakage through the caps in there, more so than a tube rectifier alone...
While its best practice to discharge always, if there is no change, don't loose sleep over it.