Performance loss when opening UI elements

[Nanakisan]

Ever since the last hotfix viewing any kind of UI element causes a massive soft-lock. FPS isn't reflective of the issue however the Peak values shows massive delays.

Before opening foundry
https://drive.google.com/open?id=1G06YcdsX6P1Q7hwoFlh9VoGRspjMqJQg
 

After opening foundry
https://drive.google.com/open?id=1D9gZ2nbVlLSZXoS4yG1I01t_Zc4pzOXU
 

Before opening mods ui
https://drive.google.com/open?id=1c3rOEQ4glI6tyrpu8U-b0jbi4G9IaPTk
 

After opening mods ui
https://drive.google.com/open?id=1Ild0m2ilMNUFgRQO3plQNtEVuzK9jhWZ
 

Also before U25 alt-tabbing the client never caused any issues. But ever since the recent hotfix alt-tabbing causes a performance loss for like 5 seconds.