Some icons reverted to default after app update

Some time ago I updated Xabber and FaceSlim, and after that their icons reverted to default. I have tried clearing cache, clearing cache and dalvik from TWRP, reinstalling and reapplying Twelf theme, nothing helped. I've waited for new theme version, but nothing changed (except for new icons I've requested thanks for that!). Am I missing something here? Is there an icon cache somewhere in /data, or something like that? I'm using Android 5.1.1 (EuphoriaOS).

P. S. Also, EasyXkcd and ownCloud Notes are still having their own icons.