When I've had issues of fields being deleted/reset, I've found the issue in the JSON file using the REST API. Typically, when you change the feature type (the symbology), it will follow a template prototype in the "types" section of the JSON file. Often a field using a domain will be set to some value instead of being inherited.
In the example below, line 7 and 8, DomainOne and DomainTwo should be inherited. Instead, if the feature type is changed from FeatureTypeTwo to FeatureTypeOne, the template section replaces certain attributes with the values shown in lines 17 through 21. If the value of the attribute is null such as FieldOne and FieldTwo, line 17 and 18, the value of those fields should retain the previous value. For the fields using DomainOne and DomainTwo, lines 19 and 20, the value will be changed to a space in this example, thus deleting the previous value. Changing the "double quote, space, double quote" to the word "null" should allow a previous value in that field to be properly inherited.
If such an issue is causing your problems, you can update the JSON file. Should you need to update the file, I can share some tips.
"types" : [
{
"id" : "FeatureTypeOne",
"name" : "Feature Type Name",
"domains" :
{
"DomainOne" : {"type" : "inherited"},
"DomaineTwo" : {"type" : "inherited"}
},
"templates" : [
{
"name" : "Feature Type Name",
"description" : "",
"drawingTool" : "esriFeatureEditToolPoint",
"prototype" : {
"attributes" : {
"FieldOne" : null,
"FieldTwo" : null,
"DomainOne" : " ",
"DomainTwo" : " ",
"MyFeature" : "FeatureTypeOne"
}
}
}
]
},
{
"id" : "FeatureTypeTwo",
....
