SUMMARY
I installed okular : sudo snap install okular
But when I wanted to run : snap run okular 
I get the following error: /snap/okular/108/kf5-launch: line 226: exec: okular: not found

STEPS TO REPRODUCE
1. sudo snap install okular
2. snap run okular

OBSERVED RESULT
/snap/okular/108/kf5-launch: line 226: exec: okular: not found

EXPECTED RESULT
Open okular pdf view document

SOFTWARE/OS VERSIONS 
Linux: Ubuntu
KDE Frameworks Version: 5.47.0 snap
Qt Version: 

ADDITIONAL INFORMATION
I had installed the snap okular application months ago and it was working perfectly, suddenly it disappeared from my application menu, I uninstalled and reinstalled it but it no longer opened the app.

The kf5-launch file referred to in the error is not inside the 108/ directory, but outside of it. But I could not move them, since they only have read permissions.

All the other snap applications I have installed (vlc, odio) are working fine, only okular stopped working.