Grails 4: Save doesn't work in service method with prefix 'set' - grails

Question

Using Grails 4.0.11 and OpenJDK 11, I came across a very strange behaviour that I was able to extract to a standalone project where I made sure it hasn't to do with plugins:
Given is a controller:
def updateOrder() {
def order = Order.get(params.id)
def result = shopService.setOrderPrintFileChecked(order)
redirect(action: "detailOrder", id: order.id)
}
and the service
#Transactional
class ShopService {
def setOrderPrintFileChecked(Order order) {
order.printFileChecked = new Date()
println("Validate: " + order.validate())
println("Errors: " + order.errors)
println("Dirty: " + order.isDirty())
def r = order.save(failOnError: true)
println("Result: " + r.printFileChecked)
return true
}
}
this does not save me the value to the database (tried MySQL+H2 default db).
If displays:
Validate: true
Errors: org.grails.datastore.mapping.validation.ValidationErrors: 0 errors
Dirty: true
Result: Sun Nov 21 15:58:17 CET 2021
if I change the method of ShopService from setOrderPrintFileChecked() to setorderPrintFileChecked() or even test() it works and the value is beeing saved correctly.**
it seems that the prefix + camelCase "setXyz" has a different behaviour. I'd like to know what it is and how to fix/prevent this case. Can provide full demo-application with the behaviour.
** Update**
This is de de-compiled service class with a non-setter-name:
public Object updateMyValue(final Order order) {
final Reference order2 = new Reference((Object)order);
final CustomizableRollbackTransactionAttribute $transactionAttribute = new CustomizableRollbackTransactionAttribute();
$transactionAttribute.setName("ch.pacdesigner.ShopService.updateMyValue");
final GrailsTransactionTemplate $transactionTemplate = new GrailsTransactionTemplate(this.getTransactionManager(), $transactionAttribute);
return $transactionTemplate.execute((Closure)new ShopService._updateMyValue_closure1((Object)this, (Object)this, order2));
}
this is the compiled method
public Object setOrderPrintFileChecked(final Order order) {
final CallSite[] $getCallSiteArray = $getCallSiteArray();
ScriptBytecodeAdapter.setGroovyObjectProperty($getCallSiteArray[0].callConstructor((Object)Date.class), (Class)ShopService.class, (GroovyObject)order, (String)"printFileChecked");
$getCallSiteArray[1].call((Object)order, (Object)ScriptBytecodeAdapter.createMap(new Object[] { "failOnError", true }));
return true;
}

Answer 1

As #Jeff Scott Brown stated, this behaviour is due to:
https://github.com/grails/grails-data-mapping/blob/c69add974963a3a1fcab27271d7ab4fa7c1faee2/grails-datastore-gorm/src/main/groovy/org/grails/datastore/gorm/transform/AbstractMethodDecoratingTransformation.groovy#L113