I thought actually that’s a problem of Carla, but falkTX (KXStudio maintainer) said it’s related to renoise.
Here’s an example file that crashes as soon I switch to the sampler. Somehow it’s related to the actual chosen sample. After deleting it it works.
Renoise file is here: https://mega.nz/#!Wvhk0aZb!18avtqy1ohzsrs5CkYDyXYV5x5J-0O3TG9wTNfWY-jg
falkTX could reproduce it, so I guess that should also work for you.
and here’s the crash log: https://pastebin.com/s4uyk2ap
System: Debian Buster with XFCE