Skills Panel / Hotbar broken

Hi,

I'm experiencing the following problem with my Skill Panel / Hotbar:

- Some skills disappear in the hotbar after entering or leaving a instance (map) through a portal. In my case it's Frost Bomb and Pain Offering.
- Other skills, for example Elemental Weakness, are not affected

--> see Screenshots

What I already tried:
- Repair game files in Steam
- Use different Slots in Skill Panel for affected Skills
- Change Slots in Skill Panel with working Skills

Hotbar as intended:


Hotbar after entering instance/map:

i specifically have this problem with level 20 pain offering gem. but not with level 19 pain offering gem... :/ the skill (pain offering in my case) will unbind from the hotbar when i go into a portal

addendum: level 21 gems still has this problem as well :(