Hello! Someone on curseforge was showing that EMS crashes with other mods and the error looks like conflicting coremods. I took a look and it seems you are trying to patch this Mojang bug like a lot of other people are trying to do as well: https://bugs.mojang.com/browse/MC-189565

However, when I look at the mixins that EMS does, it seems it uses an Overwrite mixins which is highly discouraged as overwrites are strictly not compatible with any other mixin and will crash anyone else trying to fix this bug.
https://github.com/andersblomqvist/enhanced-mob-spawners/blob/master/src/main/java/com/branders/spawnermod/mixin/EndermanEntityMixin.java

Instead, I would encourage you to take this mixin Draylar gave me which uses an Inject mixin to solve the bug but also allows other people to do inject mixins as well without crashing each other. This would be the most mod compatible way of solving this issue.
https://github.com/TelepathicGrunt/RepurposedStructures/blob/master/src/main/java/com/telepathicgrunt/repurposedstructures/mixin/EndermanSpawnerMixin.java

I hope this helps! I can explain how the Inject mixin works if you need me to.

Thanks for heads up. Issue has now been fixed