IR file is not recalled after restarting the host

[unfa]

I had this problem in the past with Ardour - that's why I stopped using IR, because reloading session caused all IR plugin instances to forget their IR files, making them no use for long-term projects.

Now I had this working fro few months in Carla plugin host, but recently my Carla projects using an IR plugin as a base failed to load the IR sample consistently for a few days.

I tried replacing it IR.lv2 with KlangFalter, but it also failed to recall the file.

I'd like to find out if this is a host- or plugin-related problem.

Here's details of my usage of IR.lv2: https://www.linuxmusicians.com/viewtopic.php?f=11&t=16638&sid=4b6df525371a990dfa9f04ba9e937653