Theme manager advanced variable gives error on theme create

Wappler Version : 5.3.3
Operating System : Mac OSX
Server Model: node.js
Database Type: mariadb
Hosting Type: local - docker

Expected behavior

Added Variable should save as others do.

Screenshot 2023-01-31 at 09.42.53752×302 5.52 KB

Actual behavior

What actually happens?
I get this error and theme is not created

Screenshot 2023-01-31 at 09.43.06730×490 37.7 KB

How to reproduce

Add Advanced variable for fonts - size-sm and change or even keep the same. The error happens on both.