Hello, sorry for the delayed answer, here's my plugin list and the crash log of the new project.
I encountered the same problem; it appears to be a conflict with YEP_BuffStatesCore, assuming you correctly set <Hide State Bar> and made the skill guaranteed to inflict Guard on yourself (e.g., something like 1000% if your max is higher than 100).
The plugin instructions, for some reason, specify <Hide Status Bar> instead of <Hide State Bar>; however, the demo project and plugin code make it clear that it's the latter. This is not properly evaluated if YEP_BuffStatesCore is enabled.
I was able to implement a quick fix (of debatable quality) by following these steps (obviously, I'm still waiting on an official fix):
1. Put Neel_SoulsStatusBar under YEP_BuffsStatesCore (which you have already done)
2. Add the following line of code:
This line of code skips the drawStatusBar function if it detects that the color is not an integer (which means it will not work if you decide to give a hidden state bar a color). There are other functional incompatibilities involving note tags (e.g., special status behavior with YEP_BuffStatesCore), but this should at least ensure that normal statuses function correctly with it installed.