When the log level is set to "all", Spigot is not starting.
I made a "log4j2.xml" file and launch Spigot with the following command :
"java -Dlog4j.configurationFile="log4j2.xml" -jar "spigot-1.12.2.jar""
It seems that the configuration is not loaded when Spigot try to check disabled advancements.