expression is lost in user parameter after close/open

Software Natron
1

Hi,

I have a user parameter called “audio_file” of the type “Text Input”:
image

I need this to hold the value of a python variable that is defined on startup via the -c flag like so:

Natron -c "audio_file_path='/tmp/audio/043_0110.wav'" test.ntp

When I first create teh user parameter and set the expression it works as expected:

image

But when I close and re-open the script it breaks:

image

This even happens when I don’t set the expression until after I close and re-open the script.
I also tried using a user parameter of the type “Input File” but to no avail.

Am I doing something wrong or is this a bug?

EDIT:
When I use an AudioCurve node’s audio parameter instead of a user parameter this works just fine, so I assume this is a bug?!

Cheers,
frank