Flatpak dev question: app cannot load shared library during runtime

Hello, I have a problem with using a shared library. The app can download and save .so files to ~/.var/app/app.ID/ but then it throws error that it cannot load it when necessary.

Problem occurs when I try to use Widevine in Opera, I verified that the file is present (Opera flatpak can download it again when missing), even gave it 777 permissions but to no avail. Error follows:

[409:213:0224/230159.556383:ERROR:cdm_module.cc(114)] CDM at /home/user/.var/app/com.opera.Opera/config/opera/WidevineCdm/4.10.2557.0/_platform_specific/linux_x64/libwidevinecdm.so could not be loaded.
[409:213:0224/230159.556599:ERROR:cdm_module.cc(115)] Error: /home/user/.var/app/com.opera.Opera/config/opera/WidevineCdm/4.10.2557.0/_platform_specific/linux_x64/libwidevinecdm.so: cannot open shared object file: Operation not permitted

Thanks for any help.