Changing an HDA parameter doesn't dirty nodes in TOP network

[ron2812]

Hi!

I have a TOP network with various HDAs with parameters (using hdaprocessor nodes)
Additionally I have multiple "HE_OUT" nodes to cook them separately in UE4 (I'm using Houdini Engine V2).
The parameters of the HDAs are collected in the parameter interface of the final PDG-HDA.

If I change a parameter in UE4 and cook the TOP-Node (that includes the hdaprocessor in his graph and corresponds to this parameter), nothing changes.
Doesn't even work if I dirty the TOP-Node.
Only when I dirty the TOP-Network and re-cook, I get the expected results.

This isn't very practical since I don't wanna dirty & cook my whole network.

Maybe this is a bug, or I'm doing something wrong?

What I wanna achieve is this:
A parameter change in UE4 only dirties the corresponding hdaprocessor (and everything below).
When I re-cook the Top-Node everything below the dirtied hdaprocessor should re-cook - nothing else.

PS:
I tried to dirty the node via Python in the callback of the parameters, but this seems to mess up the UE4/HE connection so that nothing is cooked anymore when I re-cook inside UE4.

Thanks,
Ron