Java Json Schema 'Unknown keyword else - you should define your own meta schema.'

Hello, I setup version 1.0.72 of your validator package (really great btw) in a spring boot application to validate incoming JSON requests. Validation works, what confuses me is a warning

com.networknt.schema.JsonMetaSchema :  :  Unknown keyword else - you should define your own Meta Schema. If the keyword is irrelevant for validation, just use a NonValidationKeyword

I am instantiating the schema factory for the 2020-12 draft:

final JsonSchemaFactory schemaFactory = JsonSchemaFactory.getInstance(SpecVersion.VersionFlag.V202012);

and the if/then/else object:

...

   "if":{
      "properties":{
         "key":{
            "const":"api_usage_count"
         }
      }
   },
   "then":{
      "properties":{
         "value":{
            "type":"number"
         }
      }
   },
   "else":false

Now I experimented with saying "else": {} or "else": false (since i do not really need the else block in my particular use case) but omitting the else block completely by not defining it results in a JsonParseException from Jackson.

Is there any way to either fix the warning, or not define the else block at all without the JsonParseException to be thrown?

networknt / json-schema-validator

Java Json Schema 'Unknown keyword else - you should define your own meta schema.' #992