Versions

Version 1.12.2

Scaling Health:1.3.40
Silent Lib: 3.0.13
Forge:14.23.5.2847
Optifine Installed

Scaling Health can't be connected with the Classic Bar's design:

To reproduce

1. Instals both mod, Classic Health mod and Classic Bar
2. Go to the survival world
3. See health bar and try to use the health+ item

In 1.14+ there is a config option to deactivate SH heart rendering. Not sure if it is in 1.12 too though.
If it is not, sadly I do not dev for 1.12 so won't be able to fix this issue

Will not be addressing 1.12 issues, sorry for any inconvenience, I hope you will continue playing on the 1.16.5 version which I will be maintaining.

Oh 1.16.5 will comes out, guess I just have to update it lol